Giorn. Bot Ital. 2: 189. 1846. Lectotype (Fink, 1910): B. rosella (Pers.) De Not.

Crustose lichens with sessile apothecia lacking a thalline margin, photobiont chloroccoid, asci Bacidia-type, with 8 colorless, cylindrical to acicular, multiseptate spores, conidia filiform, curved. Reference: Ekman, 1996.

Bacidias are apparently rather gregarious in the sense that collections frequently contain more than one Bacidia species. If one is not careful this can lead to confusion. Further puzzlement can arise from the propensity in some species for variation in apothecial pigmentation, usually loss of pigment(s), leading to a markedly different look to the apothecia from typical forms. They are not included in Ekman’s (1996) key but he notes some of them in the discussions. Bacidia schweinitzii and B. granosa are the worst offenders but one should be alert for as yet unnoted instances in other species.

Species of other genera are unlikely to be confused with species of Bacidia with needle-like ascospores. However, Lecania cuprea, Micarea peliocarpa, Scoliciosporum chlorococcum, S. umbrinum and possibly Myxobilimbia sabuletorum could be confused with those species of Bacidia having shorter, rod- or club-shaped ascospores and for this reason are included in the key.


1. Growing on bark, decorticate wood or bryophytes on bark
1. Growing on rock or bryophytes on rock or soil
2. Growing on bark
2. Growing on decorticate wood or on bryophytes at base of trees
3. Spores 30-90 µm long; apothecia often pruinose (except B. helicospora)
3. Spores 11-27(- 35) µm long; apothecia not pruinose (except Arthonia caesia)
4. Hypothecium yellow-brown, KOH+ rose, or red-brown and KOH-
4. Hypothecium or central part of exciple colorless or yellowish, KOH-; rim and outer part of exciple brown or colorless
5. Exciple, hypothecium and epihymenium partly yellowish to yellow-brown, KOH+ rose KOH+ faintly purplish or KOH-; apothecia typically orange-brown with white pruinose margin or dull, light purplish brown without pruina 
5. Exciple red-brown or orange-brown, deeper purple-brown in KOH; apothecia typically with blackish disk and dull brown or blackish margin (but pigment deficient forms may be clear rust-brown or whitish), sometimes pruinose when young; epihymenium green; spores 32-88 × 2-4.3 µm; very common
6. Pigmented parts distinctly KOH+ rose
6. Pigmented patches of epihymenium and rim of exciple KOH+ faintly purplish, otherwise KOH-
Bacidia schweinitzii (Michener) A. Schneid. (apothecial pigment variant)
7. Thallus granular; spores 32-69 × 2-4 µm; common
7. Thallus smooth; spores 31-74 × 2-5 µm; occasional 
8. Thallus not granular, not papillose; apothecia dark
8. Thallus granular
9. Apothecia pruinose, especially when young; spores 38-91 × 2.5-4.3 µm, not spirally twisted; common
9. Apothecia never pruinose; spores 33-81 × 2-3.7 µm often spirally twisted; occasional
10. Apothecia yellowish or pale buff, with pruinose margin; granules not papillose; rare
Bacidia diffracta S. Ekman (pigment deficient form)
10. Apothecia pale orangish; thallus of isidioid granules; granules strongly papillose; only a single collection from Carter Co., Missouri
11. Spores 2.5-5 µm wide
11. Spores 1.2-2.5 µm wide, thin-walled
12. Apothecia ± flat with an obvious margin
12. Apothecia swollen; margin absent or obscured
13. Apothecia margin smooth
13. Apothecial margin crenulate or denticulate; apothecia flat, black; spores narrowly cylindrical to narrowly clavate, with weakly acute ends, 3(-5)-septate, (13)-18-27 × 2-3 µm; rare
14. Exciple of hyphae with narrow lumina, enlarged only in outermost cells
14. Exciple of hyphae with enlarged, ellipsoid or ± isodiametric lumina
15. Epihymenium lacking granules; epihymenium and exciple green or colorless in albino forms; spores narrowly clavate or narrowly cylindrical, with weakly acute ends, 3-septate, 19-28 × 2.5-3 µm; common
15. Epihymenium with numerous to sparse blackish granules; epihymenium and exciple lackig green pigment; spores narrowly clavate to narrowly cylindrical, with weakly acute ends, 3-septate, 18-22 × 2.5-3 µm; rare
16. Hypothecium colorless; exciple dark inside; spores 3-septate, 14-15 × 2.5-3.5 µm; a single collection from Cherokee Co., Kansas 
16. Hypothecium dark gray; exciple colorless; spores 3-septate, 11-12 × 4-4.5 µm; a single collection from St. Francois Co., Missouri
17. Thallus not leprose; thallus and apothecia C+ (gyrophoric acid); apothecia white to black, often mottled; spores 3-septate, 15-23 × 3-5 µm
see Micarea peliocarpa (Anzi) Coppins & R. Sant.
17. Thallus ± leprose; thallus and apothecia C-
18. Thallus pale green, usually with a yellowish tint (usnic acid); apothecia usually bluish pruinose but occasionally blackish, without pruina; spores 3-septate, 15-24 × 4-6 µ
see Arthonia caesia (Flotow) Kôrber
18. Thallus dark green; apothecia black, shiny, never pruinose; spores, 3-7-septate, 22-34 × 3-5 µm
see Scoliciosporum chlorococcum (Stenh.) Vezda
19. Apothecia brown; exciple in part brown; hymenium brown streaked; rare 
19. Apothecia whitish or pallid; apothecial tissues colorless; rare
20. On decorticate wood
20. On bryophytes
21. With distinct, superficial thallus
21. Without obvious thallus; apothecia whitish, tiny; spores 3-septate, small
see Absconditella lignicola Vezda & Pisút
22. Thallus and apothecia C-, shades of brown
22. Thallus and apothecia C+ pink (gyrophoric acid), white to black, often mottled; spores 3-septate
see Micarea peliocarpa (Anzi) Coppins & R. Sant.
23. Apothecia pale yellowish tan; spores broad, 3-5-septate, broad, 5-6.5 µm wide; Carter Co., Missouri
see Myxobilimbia sabuletorum (Schreber) Hafellner (pale apothecia form)
23. Apothecia brownish black, spores narrow; 1.5-2 µm wide a single collection from Union Co., Illinois
24. Spores fusiform, 3-5(-7)-septate, 5-8 µm wide, with punctate outer layer; apothecia usually swollen with margin mostly hidden, not pruinose 
see Myxobilimbia sabuletorum (Schreber) Hafellner
24. Spores needle-like, multiseptate, without punctate outer layer; apothecia with persistent margin, pruinose
25. Growing directly on rock
25. Growing on bryophytes on rock or soil
26. Thallus ± thin, not compose of isidium-like granules or thallus not evident
26. Thallus thick, composed of isidium-like granules; apothecia blackish green, slightly sunken among granules; spores 3-septate, 15-17 × 3.5-4.5 µ; on noncalcareous sandstone; known from one Illinois collection just east of Ozark region
27. Spores not spirally arranged in ascus and not remaining ± spiral when released from ascus
27. Spores spirally arranged in ascus, remaining ± spiral when released from ascus; apothecia dark brown, emarginate
see Scoliciosporum umbrinum (Ach.) Arnold
28. Spores short-cylindrical, 3-5-septate
28. Spores needle-like, 3-many-septate; cross walls sometimes not readily visible
29. With obvious superficial thallus
29. Without obvious thallus or thallus scant, ± leprose
30. Thallus and apothecia C-; hypothecium brown; spores ± fusiform, often narrower at one end, 3-septate
30. Thallus and apothecia C+ pink (gyrophoric acid); apothecia without obvious margin
see Micarea peliocarpa (Anzi) Coppins & R. Sant.
31. Mostly on calcium rich rocks; exciple ± entirely dark merging with brown hypothecium; spores 13-18 × 2.5-3.5 µm
31. Always on siliceous rocks, especially chert; exciple dark at margin, remaining distinct from brown hypothecium; 12-14 × 4-5 µm 
see Fellhanera silicis R. C. Harris & Ladd
32. Apothecia pale tan or pale reddish, emarginate
32. Apothecia black, with persistent raised margin; spores 5-7-septate, 20-27 × 5-6 µm; on sandstone; occasional
see Cresponea premnea (Ach.) Egea & Torrente var. saxicola (Leighton) Egea & Torrente
33. Apothecia tan, convex; margin obscured; apothecial tissues colorless except exciple rim brown tinted; spores 3-septate, 16-21 × 2-3 µm; on dolomite; rare
see Lecania cuprea (A. Massal.) v.d. Boom & Coppins
33. Apothecia reddish, perithecium-like; spores 3(-5)-septate, 12-18(-21) × 5-6 µm; on sandstone; very rare
see Thelopsis rubella Nyl.
34. Spores short and narrow, less than 2.5 µm wide
34. Spores longer and broader, 38-91 × 2.5-4.3 µm, with many cross walls; mostly on bark, very rarely on calcium rich rock
35. Apothecia blackish; epihymenium green; hypothecium usually brownish; rim of exciple tinted green or green mixed with brown; on carbonate rock; rather common
35. Apothecia or apothecial disk pale (pinkish, brown or pale tan mottled greenish); on silicate rock; rare
36. Apothecia whitish or pale pinkish orange; hypothecium colorless
see discussion of Bacidina phacodes
36. Apothecia darker; hypothecium brown
37. Apothecia usually remaining ± flat; spores needle-like, 4 µm or less wide
37. Apothecia usually swollen, with margin mostly hidden, brown-black to whitish; spores broad, 5-8 µm wide, fusiform, 3-5(-7)-septate, with a punctate sheath; common, over lime rocks and occasionally soil
see Myxobilimbia sabuletorum (Schreber) Hafellner
38. Rarely growing from calcium rich rock onto bryophytes; spores 38-91 × 2.5-4.3 µm, with many cross walls, without punctate sheath; apothecia pruinose
38. On calcium rich soil; spores needle-like, tapered, 3-7-septate, 25-45 × 2-3 µm; apothecia not pruinose; epihymenium green; hypothecium brown; not known from Ozark region but might be expected as occurs in central Kansas
[Bacidia bagliettoana (A. Massal. & De Not.) Jatta]


Bacidia circumspecta (Nyl. ex Vainio) Malme

Bot. Notiser 1895: 140. 1895. Lecidea bacillifera var. circumspecta Nyl. ex Vainio, Meddeland. Soc. Fauna Fl. Fenn. 10: 22. 1883.

Illustrations: Ekman (1996), figs. 6C,D, 8E,F, 40G.

Thallus on bark, olive-tan, grayish or rarely dark olive-brown, superficial, areolate or occasionally mostly granular, marginally with areoles dispersed, centrally with areoles appressed, forming a ± continuous thallus, occasionally ± rugose; areoles initially ± round but soon irregular, flattened to convex, 0.1 mm (young) to ca. 1.5 mm. Apothecia variable in color, black or mottled with various combinations of black, dark brown, shades of yellow-brown, green, whitish or ± colorless, rarely entirely pale tawny yellow, scattered, sessile, flat or moderately convex, rounded or sometimes irregular and even warty with age, constricted at base, 0.5-1.0 mm across,; margin usually initially evident, slightly raised, persistent or becoming obscured in more convex apothecia, with rim in paler apothecia usually black or greenish black, pale below and darker than disk; disk pigmentation discontinuous, appearing as dark dots when wetted (except in very pale apothecia). Exciple in section under dissecting scope with a distinctive glassy aspect, diffusely pigmented at rim, green (KOH-), usually mixed with purplish brown (KOH+ purplish), especially inward and/or below, colorless in center; outer part consisting of radiating hyphae with end cells enlarged, pyriform, to 5 µm across, central part (under hypothecium) of intertwined hyphae. Hypothecium colorless, loosely prosoplectenchymatous with some enlarged cells, ca. 30-40 µm thick. Epihymenium with clumped dark green pigment or in paler forms ± colorless (KOH-). Hymenium streaked with dark green (KOH-), or ± colorless, ca. 50-60 µm thick. Paraphyses ± unbranched, some with end cells enlarged, pyriform, with a green sheath (sheath extending downward a cell or two), ca. 4-5 µm across, others little or not enlarged, without colored sheath, ca. 2 µm across. Ascospores narrowly clavate or narrowly cylindrical, with weakly acute ends, 3-septate, 19-28 × 2.5-3 µm. Pycnidia pyriform, green above, with or without brownish layer below green, colorless below, 20-30 µm across. Conidia filiform, curved, 20-25 × 0.8 µm.

Chemistry: no lichen substances detected.

Parasymbiont: ?Nectriopsis

Perithecia rose colored (KOH-), superficial, ± tomentose; hairs short, colorless, very irregular, contorted and multilobed; ascospores broadly ellipsoidal, smooth, 9-10 × 6-7.5 µm [Missouri. Greene County, Buck 38314, 38328 , also on a sterile crust from Kentucky, Buck 39904 (all NY)].

Conservation status: XXXXX.

Occasional on shaded hardwood boles, Juniperus and once on bryophytes, usually associated with other species of Bacidia. Scattered across temperate U.S. and southern Canada with the exception of the Plains and Rockies, Europe (Ekman, 1996, fig. 21).

The common forms of B. circumspecta with mottled apothecia are easily recognized, those with black apothecia will require an apothecial section to see the mostly colorless exciple (glassy under dissecting scope), colorless hypothecium and short, mostly clavate, 3-septate ascospores. Although the ascospores of B. circumspecta specimens from outside the Ozarks can have as many as seven septa (Ekman, 1996), only 3-septate ascospores have been observed in the Ozark population. However, the ascospore length of the Ozark population (_ = 23) differs little from that of the general North American population studied by Ekman (_ = 24). Ekman (1996) describes three conidial types. Only one, the curved, filiform type, is found in the Ozarks. It seems possible that molecular studies may find B. circumspecta, as presently circumscribed, to be a species aggregate. Assuming that Lecania naegelii (Hepp) Diederich & v. d. Boom is correctly placed in Lecania, Ekman’s (1996) retention of B. circumspecta in Bacidia is puzzling. They differ in ascospore size and shape but apothecial pigmentation (especially the mottling and the dotted appearance when wetted), excipular anatomy, paraphyses with a green sheath above and conidial type seem identical. Inclusion of taxa without a thalline margin in Lecania is relatively recent and will probably come under scrutiny again if the corticolous species are revised. We suggest that B. circumspecta must be included in any such revision.

Bacidia crenulata R. C. Harris & Ladd, sp. nov.
Similis B. granosae excipuli structura et colore sed corticola, hypothecio incolorato et ascosporis longioribus , (13)-18-27 × 2-3 µm; similis B. circumspectae ascosporae aspectu sed excipulo fusco et apotheciis planioribus. Differt omnibus congeneribus margino crenulato, denticulato vel radiatim sulcato.

Bacidia crenulata (Harris 44745-F) 

Thallus on bark, whitish, ± immersed, with algal layer discontinuous looking like irregular, very flat, greenish areoles or pushing through upper layer of bark forming slightly raised greenish areoles. Apothecia black, lightly shiny, scattered to ± clustered, sessile, persistently flat, strongly constricted at base, 0.3-0.6 mm across; margin black, concolorous with disk, not pruinose, usually raised, occasionally ± level with disk, persistent, variously crenulate, denticulate or weakly radiately grooved, occasionally smooth; disk black, not pruinose. Exciple brown, paling to ± colorless at edges, usually colorless in center, ca. 30-40 µm thick; pigment(s) located between excipular hyphae, dense, often in large clumps (KOH+ purplish); hyphae radiating with end cells enlarged, ± pyriform, with thick sheath, ca. 8 µm across (lumen ca. 4 µm). Hypothecium colorless, ca. 50 µm thick, of intertwined hyphae with scattered inflated cells. Epihymenium dark gray-green, (KOH-), ± uneven as some paraphysis tips not pigmented. Hymenium colorless, ca. 50 µm thick. Paraphyses mostly unbranched, many with end cells enlarged, ± pyriform, ca. 5 µm across, with a gray-green sheath, others with end cells not or only a little enlarged, ca. 2 µm across, without a colored sheath. Asci clavate. Ascospores narrowly cylindrical to narrowly clavate, with weakly acute ends, mostly 3-septate, a few seen with 4-5 septa, (13)-18-27 × 2-3 µm (_ = 20.5 µm). Pycnidia semi-immersed, ± globose, with brown wall above, colorless below, ca. 1.0 mm across. Conidia filiform, strongly curved, not obviously septate, ca. 15-20 × 0.8 µm, or mixed with rod-shaped conidia, ca. 7-9 × 1.0 µm (Buck 32738).

Parasymbiont: none encountered.

Conservation status: XXXXX.

I am not aware of any other species of Bacidia with a consistently crenulate or denticulate margin. Before the light dawned, Bacidia crenulata (named for the unique margin) was determined as either B. circumspecta or B. subincompta (Nyl.) Arnold which it somewhat resembles in pigmentation but not in the anatomy of the exciple, which seems identical to that of B. granosa. In addition to the crenulate exciple, B. granosa differs in growing on rock, brown hypothecium and shorter and slightly broader ascospores and B. circumspecta (with which B. crenulata grows) differs in dark exciple and apothecia not pure black, often greenish or yellowish, especially the disk, with a thicker margin, often becoming convex. The co-occurrence of two types of conidia in a single pycnidium needs to be confirmed with additional material.

MISSOURI. Barry County: Roaring River State Park, ravine N of cabins NW of Nature Center along CR F, 36° 34'50"N, 93° 50'00"W, E-facing slope with dolomite outcrops in Quercus-dominated forest, on bole of Juniperus with B. circumspecta and B. diffracta, 3 Nov 2000, Harris 44745-F (NY); Reynolds County: Johnson Shut-Ins State Park, along East Fork of Black River, 37° 32'N, 90° 50'W, on Juniperus, E side of river, 13 Oct 1993, Buck 24199 (NY), W side of river, 9 Oct 1997, Buck 32738 (NY), MOFEP site 6, Deer Run State Forest, just N of Shannon County line, in upland woods and upper ravine of Paint Rock Creek, at base of 6.7" DBH Quercus stellata, 1 May 1996, Chadwell s.n. (Ladd).

Bacidia diffracta S. Ekman
Opera Bot. 127: 72. 1996.

Illustrations: Ekman (1996), figs. 40H, 43F.

Thallus on bark, pale to medium green-gray, rarely pale tan (badly dried specimens?), superficial, consisting of sparse to crowded, globose to flattened and slightly irregular granules on a whitish "hypothallus" of hyphae mixed with upper cells of bark; granules 50-120 µm across, with outer layer one hypha thick. Apothecia bright to dark orange-brown (yellowish to pale buff in pigment deficient forms), pruinose or not, scattered, sessile, ± flat to strongly convex, rounded or weakly lobed in old age, constricted at base, 0.5-1.2 mm across,; disk sometimes weakly white pruinose; margin concolorous with disk or slightly darker, even with disk or obscured in convex apothecia, often strongly white pruinose; young apothecia initially globose, paler, yellowish to pale orange-brown, often strongly pruinose, with marginal pruina radiately sulcate. Exciple distinctly two parted: inner, thicker part lens-shaped, pale yellowish, of dense, gelatinized, irregular hyphae with narrow lumina, to ca. 200 µm thick; outer cup-like, of radiating hyphae with broader lumina, to ca. 100 µm thick, with terminal cells only weakly expanded, sometimes containing large, colorless crystals, ± colorless outside, yellowish to yellowish brown inward; rim usually brownish; pigmented areas of both KOH+ rose. Hypothecium yellowish to yellow-brown, ca. 40-50 µm thick, KOH+ rose above, KOH- below; hyphae irregular, not gelatinized, with some cells inflated (to ca. 6 µm across or oval, 12-15 × 6-7 µm). Epihymenium colorless to pale yellow-brown (KOH+ rose). Hymenium sometimes streaked with yellow-brown above (KOH+ rose), ca. 90-100 µm thick. Paraphyses unbranched, not or slightly expanded at tips. Ascospores needle-like, 3-11-septate, 32-69 × 2-4 µm (Ekman, 1996), not spirally arranged in ascus. Pycnidia pale brown (KOH-), ± globose, ca. 150 µm across. Conidia filiform, curved, ca. 20 × 0.8 µm.

Chemistry: atranorin (sometimes only a trace), rarely with a trace of zeorin (Ekman, 1996).

Parasymbiont: Opegrapha diffracticola, see below.

Conservation status: XXXXX.

The granular thallus in combination with the usually bright orange-brown, marginally pruinose apothecia normally allow for easy identification with just a handlens. The apothecia of B. polychroa are very similar but the thallus is smooth (for some additional minor differences see discussion of B. polychroa). The granular thallus also allows one to deal with the few specimens with pigment deficient apothecia (all tissues KOH-). One collection (Missouri, Crawford Co., Ladd 11932) has both typical and pigment deficient forms growing intermixed. The pigment deficient forms might be confused with B. rubella (Hoffm.) A. Massal. which has larger thallus granules and has not been found in the Ozark ecoregion. Pigment deficient forms of B. schweinitzii with orange-brown apothecia also tend to have granular thalli but the exciple/hypothecium is darker and KOH-. Bacidia diffracta occasionally occurs without apothecia and then can be confused with sterile Phyllopsora or sterile Bacidia schweinitzii. Phyllopsora species in the Ozarks differ in larger, proliferating thallus granules, lacking atranorin, and more conspicuous, superficial hypothallus. Bacidia schweinitzii usually lacks atranorin, has ± larger thallus granules and blackish pycnidia (not pale brown).

Bacidia diffracta is endemic to eastern North America from northern Minnesota to Nova Scotia to Louisiana and northern Georgia with a morphologically and distributionally anomalous population in eastern Florida (Ekman, 1996, fig. 22). It is locally abundant in the Ozarks (mostly Missouri) in mesic woodlands, ravines or along streams on shaded trunks of hardwoods (76%) or Juniperus (24%). Deciduous trees recorded are Acer, Fraxinus, Juglans, Platanus, Quercus alba, and Q. coccinea.

Opegrapha diffracticola R. C. Harris & Ladd, sp. nov.
Similis O. atrae Pers. quoad ascosporis sed in Bacidiae diffracticolae thallo et apothecio crescenti sed ascomatis nonnihil minoribus et saepe arcte aggregatis differt.

Type: Missouri. Barry County: Roaring River State Park, ravine N of cabins NW of Nature Center along CR F, 36° 34'50"N, 93° 50'00"W; E-facing slope with dolomite outcrops in Quercus-dominated forest, on thallus and apothecia of Bacidia diffracta S. Ekman on trunk of old Juniperus, 3 Nov 2000, Harris 44753 (holotype,NY; isotypes to be distributed).

Opegrapha diffracticola (Harris 44753) on thallus of B. diffracta

a. O. diffracticola (Harris 44753) on apothecium
b. O. diffracticola (Harris 44753) hymenium

Ascomata lirelliform, growing on thallus and apothecia of Bacidia diffracta, sessile, fusiform to ± oblong, undivided to once branched, 0.3-0.5 × 0.2 mm, solitary and scattered or aggregated into irregular clusters, to 3 × 2 mm; disk concealed by appressed lips. Exciple brown-black, greenish black in KOH, entire, thickened below, to 50-60 µm. Hypothecium thin, colorless. Epihymenium yellow-brown (KOH-). Hymenium colorless, I+ patchily blue-green. Asci ovoid, with 8 ± biseriately arranged spores. Ascospores remaining colorless, 3-septate, with thin halo, 13-15-4-4.5 µm. Pycnidia brown, ± globose, ca. 100 µm mm across. Conidia rod-shaped, 4.5 × 1.0 µm.

Knowledge of many groups of lichen parasites/parasymbionts is essentially inaccessible to non-specialists. It is possible that a name for this taxon exists buried somewhere but we are unaware of anything which might apply to O. diffracticola. As far as we know at this time it is confined to B. diffracta and, interestingly, does not occur on the presumably closely related B. polychroa , even when the two taxa are adjacent on a piece of bark [Harris 44745-C as B. polychroa (NY)]. Opegrapha diffracticola seems close to O. atra in septation and size of ascospores but the ascomata are smaller and often form dense clumps. Further, we have been unable to locate Trentepohlia, which would be expected in O. atra. It also lacks the olive-green coloration in KOH of epihymenium and exciple noted in Purvis et al. (1992) but eastern American material of O. atra also lacks this reaction. Opegrapha atra has not been found in the Ozark ecoregion. While the fact that ascomata and pycnidia are found on apothecia seems sufficient evidence for the parasymbiotic nature of the Opegrapha and additional confirmation was found by examining non-Ozark material of B. diffracta at NY, where an additional record from Vermont was found (We suggest that examination of collections of B. diffracta at other herbaria should reveal additional localities for the Opegrapha.). There seems to be no noticeable damage to the host when on the thallus but the apothecia are ± deformed and darkened. Bacidina assulata, although assigned to Bacidina, not Bacidia, has a very similar species of Opegrapha associated with it. See below.

Additional specimens examined. ARKANSAS. Madison County: Madison County Wildlife Management Area, along CR 30, 3.2 mi E of AR 23, 36° 14'N, 93° 41'W, dry, Quercus-dominated forest, 2 Nov 2000, Harris 44679; Stone County: 2.1 mi S of White River on St. Rd. 5, T17N, R.11W, sect. 20; seepy sandstone glade, 26 Apr 1988, Harris 21592-A. MISSOURI. Barry County: Roaring River State Park, ravine N of cabins NW of Nature Center along CR F, 36° 34'50"N, 93° 50'00"W; E-facing slope with dolomite outcrops in Quercus-dominated forest, on thallus and apothecia of Bacidia diffracta S. Ekman on trunk of old Juniperus, 3 Nov 2000, Harris 44745-B Oregon County: Mark Twain National Forest, Falling Spring, ca. 2.4 mi E of MO 19 on forest Service road 3170/3164, 36° 52'N, 91° 18'W, dolomitic bluff and old glade on W-facing slope W of Falling Spring, 17 Apr 1997, Harris 40523-A. OKLAHOMA. Cherokee County: J. T. Nickel Family Nature and Wildlife Preserve (J5 Ranch), ca. 7 mi NE of Talequah, Tully Hollow, 35° 59'30"N, 94° 51'45"W; moist hardwoods above stream, 30 Oct 2000, Harris 44238-B, 44273-A. VERMONT. Addison County: Monkton, 10 Dec 1879, Farlow (all NY).

Bacidia granosa (Tuck.) Zahlbr.
Cat. Lich. Univ. 4: 203. 1926. Lecidea granosa Tuck., Proc. Amer. Acad. Arts Sci. 5: 420. 1862.

Thallus on carbonate rock, rarely silicate rock, tan to pale brownish gray to darker ‘dirty’ gray, superficial, mostly on calcium rich rock, commonly cracked or cracked-areolate, to 50 µm thick, less often of irregular, flattened areoles ± sunken between rock crystals, rarely subsquamulose or peeling from rock, granular or virtually undetectable; well developed areoles roughened with flat warts (thallus may appear pale spotted when darker algae/cyanobacteria collect in troughs between warts). Apothecia mostly black (whitish in a rare unpigmented form in which following apothecial structures are whitish externally and ± colorless in section), not pruinose, scattered, sessile, flat to moderately convex, constricted at base, 0.3-0.8 mm diam.; young apothecia tall in proportion to width with a high proportion of margin to disk; disk black, mostly paler when wet, less commonly (in deep shade?) pale gray, pale brown-gray or medium brown, without pruina; margin black, slightly raised, mostly persistent (rarely hidden in convex apothecia or not detectable until apothecium wetted). Exciple often greenish above adjacent to hymenium (KOH-), colorless outward, dark, brown, greenish brown or purplish brown interiorly (mostly continuous under hypothecium), rarely exciple with only a little interior pigment; pigment(s) located between excipular hyphae (KOH weakly purplish); excipular hyphae radiating with end cell ± pyriform with a thick colorless sheath, 7-8 µm diam. including sheath, lumen ca. 3-4 µm. Hypothecium orange brown to brown (KOH-), rarely almost without pigment or obscured by excipular pigment. Epihymenium colorless. Hymenium often greenish and streaked with darker green (mostly around asci), occasionally colorless. Paraphyses unbranched, with end cells little expanded to pyriform, 3-4 µm diam., unpigmented. Ascospores ± fusiform, often narrower at one end, 3-septate, 13-18 × 2.5-3.5 µm, not halonate. Pycnidia usually present, globose, ca. xx µm diam.; wall often greenish above, brownish below. Conidia filiform, mostly semicircular curved, not septate, 13-18 × 1.0 µm.

Chemistry: not studied.

Parasymbiont: Lichenoconium sp. on apothecia (Kansas, Harris 44371).

Conservation status: XXXXX.

Occasional on shaded, usually moist, carbonate substrates, typically shaded dolomite outcrops in mesic ravines and along streams, also on old, shaded concrete in mesic areas, rarely on siliceous rocks in similar habitats. If not united with B. coprodes (see below), B. granosa is endemic to eastern North America, New York to Florida Panhandle, Iowa to Arkansas and Mississippi (northern extent of range not clear).

With experience the typical form with dark, marginate apothecia on a tan, cracked thallus with low warts on the areoles growing on dolomite or limestone can be identified without microscopic study but many specimens will need to be confirmed with an apothecial cross-section to see the dark exciple continuous under the hymenium and 3-septate ascospores. On calcareous rocks difficulties arise from relatively uncommon variations in apothecial pigmentation. These include forms with ± colorless hypothecium and/or reduced excipular pigmentation. Even more problematic are two completely albino collections (Kansas: Buck 38511, Missouri: Buck 38286, in both the typical form is also present on adjacent parts of the rock). In such cases one has to depend on the ascospores and general aspect to make a determination. Bacidia granosa also occurs uncommonly on siliceous rock and then distinction from Fellhanera silicis is a problem. Apothecial pigmentation is very similar but the Fellhanera has an exciple of irregularly arranged enlarged cells, B. granosa of radiating hyphae with only the end cell ± enlarged and the interior of the Fellhanera exciple is paler greenish, clearly distinct from the brown hypothecium, not dark brownish and ± continuous with the hypothecium as in B. granosa. The ascospores of F. silicis are broader, 4-5 µm versus 2.5-3.5 µm. The most definitive characters, if one has the skill and patience, are the ascus type (with a broad, pale axial mass in B. granosa, with a dark apical tube in F. silicis) and conidial type (filiform, curved in B. granosa, short, bacillar to bowling pin shaped in F. silicis, pycnidia usually present in both). Ekman (1996) notes that Bacidia coprodes (Körber) Lettau (1860) is very similar to B. granosa (1862). Based on the two specimens of B. coprodes I have seen, I would consider them synonymous but I defer to European wisdom. Further, since Ekman would not include these species in Bacidia s. str., it would be wise not to get overly comfortable with either the generic assignment or the epithet ‘granosa’.

Bacidia helicospora S. Ekman
Opera Bot. 127: 74. 1996.

Illustrations: Ekman (1996), figs. 7, 41B, 43G.

Bacidia helicospora (Buck 31861)

Thallus on bark, shades of gray, superficial or mostly immersed, essentially smooth or with slightly raised, scattered to aggregated areoles, to 50-60 µm thick. Apothecia black in sun, paler in shade, then brown to pallid, mottled with darker browns, ± shiny, not pruinose at any stage, scattered, flat, rarely weakly convex, round or ± lobed in old apothecia, 0.5-1.5 mm across; margin raised, relatively thick, especially in young apothecia, less commonly even with disk, black to brown, usually darker than disk in paler apothecia; disk black to brown, finely dotted when wetted. Exciple dark brown to pale brown in a narrow outer zone (KOH+ more purplish), tinted yellow brown within, especially in upper part, occasionally darker just below hypothecium or most of exciple tinted yellow-brown, sometimes mostly colorless (under dissecting microscope mostly shiny and brownish), 80-100 µm thick; outer part of radiating hyphae, with end cells ± enlarged; central part denser, with hyphae more irregularly arranged. Hypothecium colorless, 40-60 µm thick. Epihymenium discontinuously dark (rarely pale) brown pigmented (KOH+ purplish, rarely KOH-); pigment mostly around ascus tips and clumps of paraphyses. Paraphyses unbranched, not or only slightly expanded at tips, ca. 2-3 µm wide, sometimes sheathed by brown pigment and then ca. 4 µm with sheath. Ascospores needle-like, often twisted (often spirally twisted in ascus and released in a single bundle, especially when ± immature), broader toward one end, gradually tapering in a long tail, 11-15-septate, 47-64 × 3.5-4.5 µm. Pycnidia globose, brownish, ca. 100 µm across. Conidia filiform, curved, 20-27 × 0.8 µm.

Chemistry: no lichen substances detected.

Parasymbiont: none encountered.

Conservation status: XXXXX.

Bacidia helicospora is the only "long-spored" Ozark Bacidia with dark apothecia completely lacking pruina at all stages. Thus the flat, ± shiny, black to mottled brown/black apothecia, thin, gray thallus in combination with the microscopic characters of brown epihymenium and outer exciple and long needle-like ascospores make for ready identification. In paler forms the epihymenial pigment may not be obvious but mostly still gives a KOH+ purplish reaction. However, one specimen (Missouri, Carter County, Ladd 19511A) lacks any pigment reacting with KOH and consequently the apothecia are a clear orange-brown, not showing any fine dots when wetted. It presumably represents another instance of the variation in pigmentation we have found throughout the genus. In aspect B. helicospora might be confused with large forms of B. circumspecta which differs in much shorter, 3-septate ascospores. Small forms of B. schweinitzii completely lacking pruina differ in better developed thallus, thicker, more convex apothecia, greenish epihymenium and thick brown exciple. Ekman (1996) emphasizes the spores twisted in the ascus and the tendency for the spores to be ejected as a single bundle. However, in fresh material from the Ozarks, while a few asci can usually be found with twisted spores, the spores are not often seen released in bundles. This latter character may be one which is affected by the length of time in the herbarium since most of the specimens seen by Ekman were at least 15 years old.

Bacidia helicospora is endemic to southern and central U.S. It does not seem to be a very common species. Ekman (1996, fig. 23) maps 11 localities from Maryland to southern Oklahoma and the Florida Panhandle (including one from Ozarkian Illinois). Judging from our material, it seems to occur mostly as rather small, scattered thalli, often only found as an admixture in other Bacidia collections. We have only nine collections of B. helicospora from the Lower Ozarks and northern Arkansas, three are from Juniperus branches, one from a dead branch of Pinus echinata and five from trunks of hardwoods (Acer, Carya & Quercus).

Bacidia melanosticta R. C. Harris & Ladd, sp. nov.
Species insignis epihymenio granulis atris, hymenio brunneo tincto, excipulo partim brunneo et ascosporis 3-sepatatis, 18-22 × 2.5-3 µm.

Thallus on bark, tan, superficial, older parts cracked into irregular areoles ca. 0.3 mm across seemingly composed of smaller areoles less than 0.1 mm across, to ca. 75 µm thick, not corticate, youngest parts with dispersed, flattened, irregular areoles ca. 0.1 mm across, without evident prothallus. Apothecia uniform dark brown in sun, mottled brown and tan where shaded, not pruinose, scattered, sessile, flat to ± convex; margin concolorous with disk or slightly paler, even with disk or very slightly raised, evident from beginning, persistent but becoming less evident in older apothecia. Exciple variably colored, translucent brown, mostly toward outside, otherwise colorless (KOH slightly purplish brown), ca. 30-50 µm thick; excipular hyphae radiating, with end cells ± enlarged, ca. 4 µm across, with brown pigment located between the hyphae. Hypothecium with thin brownish layer above, otherwise colorless, ca. 30-40 µm thick, extending downward stipe-like. Epihymenium colorless, with few to many, irregular, brown-black granules, to 5 µm across, KOH-, not dissolving, N-, dissolving. Hymenium partially or entirely diffusely brown tinged, ca. 50 µm thick (KOH slightly purplish brown). Paraphyses unbranched, not pigmented, with end cells not enlarged (ca. 2 µm across) or enlarged, ± pyriform (ca. 4 µm across). Asci short clavate. Ascospores narrowly clavate to narrowly cylindrical, with weakly acute ends, 3-septate, 18-22 × 2.5-3 µm. Pycnidia with upper part green, lower part brown. Conidia filiform, curved, ca. 20 × 0.8 µm.

Chemistry: not studied.

Parasymbiont: none encountered.

Conservation status: XXXXX.

As far as we are aware there are no other species of Bacidia with blackish granules in the epihymenium (from which the epithet is derived). Also the total lack of greenish pigments is noteworthy as is the diffuse nature of the brown pigment and the weakness of its reactions with the usual reagents. The dull brown-black obscurely marginate apothecia of B. melanosticta are fairly distinctive but could confused with some forms of B. circumspecta which differs in the presence of greenish pigments in the apothecium and larger ascospores. It is known only from a single collection on a substrate which is rarely collected.

MISSOURI. Shannon County: MOFEP site 4, in Cardareva State Forest, S of Banker Hollow, W of Wolf Pen Hollow, N of Current River, on Toxicodendron radicans along bank of Current River, Apr 1996, Chadwell s.n. (Ladd).

Bacidia polychroa (Th. Fr.) Körber
Parerga Lich. fasc. 2: 131. 1860. Biatora polychroa Th. Fr., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 12: 17. 1855.

Illustrations: Ekman (1996), fig. 41G; Wirth (1995) 1:160.

Thallus on bark, whitish to pale greenish (from a distance), superficial, with small, flat, ± dispersed areoles barely raised above bark to raised, crowded and ± constricted at base, rarely nearly continuous and cracked; areoles 0.1-0.3 mm across. Apothecia light orange-brown, buff-brown, brown or dark brown, pruinose or not, scattered, sessile, flat to rarely strongly convex, constricted at base, 0.5-1.0 mm across,; disk sometimes thinly white pruinose; margin slightly darker than or concolorous with disk, even with disk or slightly raised, obscured in convex apothecia, sometimes thinly white pruinose; young apothecia paler, light orange-brown, occasionally pruinose. Exciple distinctly two parted: inner part lens-shaped, yellowish, of dense, gelatinized, irregular hyphae with narrow lumina, to 80-120 µm thick; outer cup-like, of radiating hyphae with broader lumina, to 70-120 µm thick, with terminal cells ± expanded, clavate, sometimes containing large, colorless crystals, ± colorless outside, yellowish to yellowish brown inward; pigmented areas KOH+ rose. Hypothecium yellow-brown, 40-60 µm thick (KOH+ rose); hyphae irregularly arranged, not gelatinized, with some cells inflated (ca. 6 µm across or oval, 12-6-7 µm). Epihymenium colorless to pale yellow-brown (KOH+ rose). Hymenium sometimes streaked with yellow-brown in upper part, KOH+ rose, 80-120 µm thick. Paraphyses unbranched, not or slightly expanded at tips. Ascospores needle-like, 2-15-septate, 31-74 × 2-5 µm (Ekman, 1996), not spirally arranged in ascus. Pycnidia almost colorless to pale orange-brown, ± globose, KOH-, ca. 100 µm across. Conidia filiform, curved, ca. 20-25 × 0.8 µm.

Chemistry: no substances detected or atranorin (Ekman, 1996).

Parasymbiont: none encountered.

In addition to the smooth thallus B. polychroa seems to have some additional tendencies separating it from the very similar B. diffracta, at least in the Ozarks: sometimes no pruinose apothecia present, no young apothecia seen completely white pruinose or with pruina radiately sulcate, margin in older apothecia less pruinose, margin often darker than disk and thus more visible, disk more often thinly pruinose, apothecial color not as bright (tends more toward buff shades), and exciple and hypothecium more uniformly colored and KOH+ rose. We have not encountered pigment deficient forms in Ozark B. polychroa. Forms of B. schweiniztii with smooth thallus can be separated by its darker, redder, KOH- hypothecium, epruinose forms of B. suffusa by its ± colorless, KOH- hypothecium.

Bacidia polychroa has an eastern American-European distribution. In North America it is known from northern Minnesota to northern Maine south to western Louisiana and central Florida (Ekman, 1996, fig. 28). In the Ozark ecoregion it seems ± less common than its near look-alike B. diffracta, occuring on the trunks of a variety of hardwoods (63%) as well as trunks and dead branches or twigs of Juniperus and once on Pinus echinata. Although we have fewer collections of B. polychroa than B. diffracta, the range of hardwoods is greater, Acer rubrum, Acer saccharum, Carpinus, Carya cordiformis, Celtis, Fraxinus, Juglans, Liquidambar, Populus deltoides and Ulmus.

Bacidia schweinitzii (Fr. ex E. Michener) A. Schneid.
Guide Study Lich. 110. 1898. Biatora schweinitzii Fr. ex Schneider, in Darlington, Flora Cestrica ed. 3, 447. 1853.

Illustrations: Brodo et al. (2001), fig. 126; Ekman (1996), figs. 8A, 42D,E.

Thallus on bark, pale gray-green to dark green (shades of tan in older herbarium specimens), dull, superficial, in Ozark region most commonly ± continuous and areolate, but also coarsely granular, or rarely thallus scant with or without small granules (dry habitats?), rarely smooth and continuous (on smooth bark); areoles slightly to strongly convex, round or irregular, 0.1-0.2 mm across; when thallus coarsely granular, granules often flattened and irregular or sometimes even isidioid, when thallus scant, granules smaller, ca. 0.5-0.15 µm across; granular thalli sometimes with thin, white, arachnoid hypothallus. Apothecia most commonly entirely black or disk black and margin dull brown (pigment deficient variants described below), mostly without pruina, scattered, sessile, flat, less commonly moderately to strongly convex, rounded or slightly lobed with age (rarely old apothecia regenerating, forming a dense clump of small, deformed apothecial initials or apothecia), constricted at base,; margin concolorous or dull brown, slightly raised above or even with disk, rarely ± strongly raised, occasionally thinly pruinose in young apothecia, obscured in more convex apothecia; young apothecia often pale buff-brown. Exciple two-parted but division often ± obscured by density of pigmentation, inner lens-shaped, deep red-brown (KOH+ deep purple-brown), ca. 100-150 µm thick, of irregularly intertwined, rather large hyphae, outer cup-shaped, red-brown inside, paler outwards, yellow-brown, yellowish or colorless (KOH+ purplish), ca. 80-100 µm thick; rim often green adjacent to epihymenium. Hypothecium brown(KOH-), or concolorous and indistinguishable from the inner part of the exciple, ca. 60 µm thick. Epihymenium with dense to sparse clumps of green pigment (KOH-), often extending downward into upper hymenium. Hymenium ca. 100 µm thick. Ascospores needle-like, 3-15-septate, 32-88 × 2-4 µm. Pycnidia blackish, globose, 0.15-0.2 mm across, with upper wall dark brown. Conidia filiform, curved, 20-25 × 0.8 µm .

Chemistry: ± atranorin.

Parasymbiont: none encountered.

Conservation status: XXXXX.

Pigment deficient forms.

1) Apothecia orange-brown or yellow-brown, shiny or rarely dull. Exciple inner part uniformly light orangish brown, outer light orangish brown inside, with colorless layer outside; pigmented parts darkening slightly in KOH. Hypothecium concolorous with inner exciple. Epihymenium colorless (KOH-). Otherwise as in the typical form.

This form lacks the pigments Bacidia Green and Schweinitzii Red ( as named by Ekman, 1996). The remaining Rubella Orange, mainly in the exciple, is then responsible for the apothecial color. This form occurs occasionally throughout the range of B. schweinitzii.

2) Apothecia dull brown. Exciple inner part yellowish to light orangish brown, outer light orangish brown inside (KOH-), pale grayish or ± colorless outside (KOH+ faint purplish, C+ faint purplish). Hypothecium concolorous with inner exciple. Epihymenium spottily faint grayish pigmented or ± colorless (KOH+ faint purplish, C?). Otherwise as in typical B. schweinitzii.

The apothecia of this form seem to lack the same two pigments as the first variant but contain low amounts of Thalloidima Green in the upper edge of the exciple and in the epihymenium. Although the concentration of Thalloidima Green seems low, it is apparently sufficient to tone down the orange-brown color seen in the first variant to a dull brown. Thalloidima Green has not been reported from B. schweinitzii and the material is included in here with some hesitation. This form is known to us from only three collections, one from Ozarkian Oklahoma, the other two from Arkansas south of the Ozark ecoregion.

2) Apothecia yellowish white, slightly shiny. All tissues colorless (KOH-) except the center of the inner part of the exciple which is pale brown in section (KOH-).

This would seem to be an almost completely albino form of B. schweinitzii with only traces of Rubella Orange. A similar form with more pigment in the exciple is known from Alabama. Interestingly the single Ozark collection of this variant is associated with both typical B. schweinitzii and the first variant above.

Typical B. schweinitzii is unlikely to be confused with any other Ozark Bacidia. The entirely black or dull brown margined black apothecia with green epihymenium and bright red-brown exciple in section (seen even with a dissecting microscope) are unique. The thallus is very variable (reduced in drier situations, increasingly better developed with increasing humidity?). The forms with lighter brown, pigment deficient apothecia might be confused with B. diffracta or B. polychroa but these have the exciple and hypothecium yellowish in section, distinctively KOH+ rose. Sterile thalli can be confused with B. diffracta or Phyllopsora ssp. See discussion of B. diffracta.

Bacidia schweinitzii is the most common species of Bacidia and one of the more common crustose lichens in eastern North America including the Ozarks. It is endemic to eastern North America from northern Minnesota to Nova Scotia south to eastern Texas and central Florida (Ekman, 1996, fig. 31). Bacidia schweinitzii occurs in moist to dry mesic woodlands and almost all collections are from lower and middle portions of trunks of hardwoods, with only two collections from decorticate Juniperus twigs and once on bryophytes on Juniperus. As might be expected with a "weedy" species, B. schweinitzii occurs on a variety of trees, Acer, Carpinus, Carya, Cercis, Cornus florida, Diospyros, Fraxinus, Liriodendron, Ostrya, Platanus, Quercus, Sassafras and Ulmus.

Bacidia suffusa (Fr.) A. Schneid.
Guide Study Lich. 110. 1898. Biatora suffusa Fr., Syst. Orb. Veget. 285. 1825.

Illustrations: Ekman (1996), figs. 3C, 42G.

Thallus on bark or rarely rock or bryophytes, whitish or rarely gray, superficial, areolate; areoles ± dispersed to crowded and becoming ± continuous, mostly nearly flat but sometimes raised and weakly constricted at base, rarely almost bullate, 0.2-0.3 mm across, with interspaces ± arachnoid and rarely with a white, fimbriate prothallus (on hard bark of Carya). Apothecia shades of brown to blackish, rarely pale, scattered, sessile, rounded or weakly lobed when old, flat to moderately convex, constricted at base, 0.8-1.5 mm across; disk mostly medium brown, chocolate brown to blackish brown, often mottled with paler browns, less commonly pale orangish brown or buff-brown, rarely yellowish, often with thin white pruina; margin usually slightly darker, even with or slightly raised above disk, frequently pruinose; young apothecia very often totally white pruinose, with marginal pruina usually denser and often radiately sulcate, sometimes rather coarse (marginal pruina sometimes remaining ± sulcate in older apothecia). Exciple distinctly two parted: inner lens-shaped, colorless or very weakly yellowish, dense, of gelatinized, interwoven hyphae with narrow lumina, 80-120(170) µm thick; outer cup-shaped, with outer part chestnut brown, especially rim (KOH-), paling to colorless inward, 90-120 µm thick, of radiating hyphae with narrow lumina inward and several rows of enlarged cells outside. Hypothecium mostly yellowish (KOH-), sometimes colorless, 50-70 µm thick, of loosely intertwined hyphae with some cells enlarged. Epihymenium with clumps of chestnut brown pigment around paraphyses (KOH-) or nearly colorless. Hymenium colorless or streaked with brown above, (KOH-), 100-120 µm thick. Ascospores needle-like, 3-17-septate, 38-91 × 2.5-4 µm. Pycnidia blackish brown, globose, ca. 100 µm across, with upper wall chestnut brown. Conidia filiform, curved, ca. 20-30 × 0.8 µm.

Chemistry: atranorin.

Parasymbiont: none encountered.

Conservation status: XXXXX.

Bacidia suffusa is the most frequently pruinose of the long spores species. Rare epruinose forms can be superficially confused with other species with brown apothecia but can be recognized by the colorless inner exciple, outer exciple with several layers of enlarged cells and lack of reactions with KOH. The young apothecia are often completely white pruinose and older ones seem to discolor readily and become very dark brown or blackish and these combined with "normal" brown apothecia give a distinctive "tricolor" aspect not seen in the other brown-fruited Bacidias.

Bacidia suffusa is an eastern North American endemic, known from northern Minnesota to Quebec south to eastern Texas and northern Florida (Ekman, 1996, fig. 33). The species is common in the Ozarks, mainly on the trunks of hardwoods, rarely on twigs, rock or bryophytes on rock and once on bryophytes on Juniperus. It seems to differ in substrate preference from other species of Bacidia which occur on Juniperus with some regularity. Bacidia suffusa has been collected on a variety of hardwoods, Aesculus, Asimina, Carya, Celtis, Diospyros, Fraxinus, Juglans, Quercus and Ulmus.

Bacidia sp.32884
Thallus on bark, pale greenish, superficial, consisting of ± spherical to irregular, isidioid granules, ca. 50 µm across to ca. 100 × 50 µm, loosely attached, weakly dispersed to crowded, without evident hypothallus; granules with coarse, bluntly conical papillae, 10-15 µm long (visible under dissecting microscope), thick-walled with small lumina. Apothecia pale orangish, not pruinose, flat to weakly concave, rounded or weakly lobed in old age, constricted at base; margin concolorous with disk, raised and ± thick in young apothecia, remaining ± raised or even with the disk in older apothecia. Exciple colorless, outer part cup-shaped, colorless, ca. 100 µm thick, of indistinct, radiating hyphae with thick walls and narrow lumina, with end cells slightly enlarged, inner part, colorless, ca. 40 µm thick, of interwoven hyphae, with thick wall and narrow lumina. Hypothecium pale yellowish (KOH-), ca. 30 µm thick, of ± loose hyphae, with some cells enlarged. Hymenium colorless, ca. 100 µm thick. Asci Bacidia-type. Ascospores needle-like, multiseptate, 46-74 × 2.5-3 µm. Pycnidia not found.

Chemistry: no lichen substances detected.

Parasymbiont: none encountered.

The strongly papillate, isidioid, granular thallus is unique as far as we can ascertain. It seems certainly new to science and as soon as more adequate material is collected, will be formally described. Superficially it might be confused with B. rubella or pale apothecial forms of B. diffracta both of which differ in mostly rounded, non-papillose thalline granules and B. diffracta has apothecial tissues KOH+ rose.

MISSOURI. Carter County: Mark Twain National Forest, along S side of Skyline Drive (FS 3280), ca. 2.8 mi SW of MO 103, 36° 57'N, 91° 02'W, 220-265 m, oak-pine-Nyssa woodland, on base of Quercus coccinea, 13 Oct 1997, Buck 32884 (NY).

Bacidia sp.44360
Thallus on bark, superficial, scattered, pale green, slightly raised areoles on a white hypothallus; areoles round to ± irregular, 0.05-0.15 mm across, to 100 µm thick, with a thin cortex. Apothecia dark gray. blackish or partly tan, scattered, sessile, flat to moderately convex, 0.2-0.5 mm across; disk medium to dark gray, grayish tan, tan or mottled gray and tan, not pruinose; margin blackish, thin, even with disk, not pruinose. Exciple outer part inside green-gray (KOH-), or mixed green-gray and brown (KOH+ purplish), colorless at edge, with hyphae radiating, with large lumina, with end cells slightly larger, with lumina to 6 µm across; cental part denser, colorless, of thick-walled, intertwined hyphae. Hypothecium colorless, of ± loose hyphae with ± large lumina. Epihymenium colorless. Hymenium colorless or faintly green streaked (KOH-). Asci Bacidia-type. Ascospores rod-shaped, 3-septate, 13-15 × 2.5-3.5 µm. Pycnidia not found.

Chemistry: not studied.

Parasymbiont: none encountered.

Externally this species is reminiscent of Lecania naegelii (Hepp) Diederich & v. d. Boom but the anatomy of the exciple does not agree with that of this group of Lecania as defined by Ekman (1996). We place it provisionally in Bacidia pending further study. It is most likely to be confused with B. circumspecta which differs in larger spores and more compact exciple. It could also be confused with Fellhanera spp. which have a dark hypothecium and different ascus type.

KANSAS. Cherokee County: N of SE Bagdad Road, 0.2 mi W of Missouri state line, 1.6 mi E of jct with US 166/400, 37° 01'35"N, 94° 36'35"W, N-S-running ravine in oak woods, on white oak, 31 Oct 2000, Harris 44360 (NY).

BACIDINA V_ zda, nom. cons. prop.

Folia Geobot. Phytotax. Praha 25: 431. 1991. Holotype: Bacidina phacodes (Körber) V_ zda.

Crustose lichens, mostly of humid microhabitats, with small, sessile apothecia, thalline margin absent, photobiont chlorococcoid, often aggregated into discrete units (goniocysts), asci Bacidia-type, with 8 colorless, needle-like, narrow (less than 2.5 µm), thin-walled, 3-7-septate spores, conidia filiform, mostly curved, rarely needle-like. Reference: Ekman, 1996.

Bacidina is a rather weak genus, held together mainly by the narrow spores and preference for humid microhabitats. It would not be surprising if Bacidina species have not arisen several times from within Bacidia. The narrowness of the spores makes the cross walls very difficult to see and apparently they are late to develop so that the spores usually appear nonseptate. Since the number of septa is not relevant to identification, we have not studied Ozark material for this character. The genus seems to species rich in the Ozarks. Unfortunately these small lichens are as yet too infrequently collected, especially on rock, to resolve all of the problems. The taxa are keyed above under Bacidia.

Bacidina assulata (Körber) S. Ekman
Opera Bot. 127: 116. 1996. Bacidia rubella var. assulata Körber, Parerg Lich. fasc. 2: 131. 1860. Bacidia assulata (Körber) V_ zda, Lich. sel. exs. fasc. 23: 566. 1967.

Thallus on bark, greenish white (darkening in herbarium?), ± continuous or of irregular, weakly raised areoles, 0.05-2.0 mm across. Apothecia brown, dark brown, rarely tan, or mottled brown and paler browns; margin concolorous, darker or lighter, often obscured (when protected from light, with disk pale buff-brown and margin pallid), scattered, sessile, ± flat to moderately convex , 0.3-0.9 mm across. Exciple brown tinted at rim (KOH-), otherwise colorless or pale outside, brownish inside, ca. 70-150 µm thick, of radiating hyphae with end cells enlarged and some inner cells also enlarged or not, with central part of intertwined, colorless hyphae with small lumina. Hypothecium colorless, ca. 50 µm thick, of intertwined hyphae with some cells enlarged. Epihymenium colorless. Hymenium streaked with yellow-brown to brown in upper part (KOH-), ca. 80 µm thick. Paraphyses unbranched, not expanded at tips, or weakly capitate, 2-4 µm across. Ascospores needle-like, 5-9-sepate, 36-43 × 2-2.5 µm (Ekman, 1996). Pycnidia immersed, colorless (Ekman, 1996). Conidia filiform, curved, non-septate, ca. 10 × 0.5 µm (Ekman, 1996).

Chemistry: not studied.

Parasymbiont: Opegrapha sp.

Ascomata as in Opegrapha diffracticola (see above) but the spores are 5-6-septate, 18-20 × 3.5-4 µm, on thallus, Wetmore 84042 (MIN). Before examining the spores, we thought that this collection would mean that O. diffracticola was not specific to Bacidia diffracta.

Conservation status: XXXXX.

Ekman’s (1996) only North American record of this species is from the Ozark ecoregion on oak (Cherokee Co., Oklahoma). The second record is on Juniperus [Taney Co., Missouri, Wetmore 84042 (MIN)]. It otherwise known from central and eastern Europe.

Bacidina egenula (Nyl.) Vezda
Folia Geobot. Phytotax. Praha 25: 432. 1991. Lecidea egenula Nyl., Flora 48: 147. 1865.

Thallus on calcium rich substrates, rarely silicate rock, pale tan or pale gray, superficial, usually of small, confluent or ± dispersed granules or areoles (goniocysts), ca. 0.05 µm across, sometimes fusing and appearing continuous or forming larger, thicker (to 150 µm) areoles around an apothecium (usually seen to be composed of goniocysts in section), when on sandstones, sometimes not readily visible, reduced to a few granules among sand grains. Apothecia dark, usually black but disk and/or margin occasionally brownish or mottled black and brown, sessile, mostly flat, sometimes convex, round, constricted at base, 0.2-0.5 mm across; margin usually slightly raised, sometimes even with disk, or obscured in convex apothecia. Exciple mostly colorless, with rim dark green adjacent to hymenium, mostly brown at edge below the green (KOH+ purplish), with brown pigmented area occasionally continuous with brown of hypothecium; outer portion cup-shaped, 50-70 µm, of radiating hyphae with end cells markedly enlarged; inner portion often with a cellular appearance, thick walled. Hypothecium mostly brown (KOH-), occasionally very pale, rarely colorless, 40 µm, of rather loose hyphae with some cells enlarged. Epihymenium and with clumps of green of green pigment (KOH-). Hymenium streaked with green (KOH-), 60 µm thick; pigment mostly associated with groups of paraphyses or with asci,. Paraphyses unbranched, some not or little expanded at tips, ca. 2.5 µm across, others expanded at tips, to 6 µm across, with a thin green sheath. Ascospores needle-like, 0-7-septate (Ekman, 1996), 23-31 × 1.5-2 µm. Pycnidia blackish, immersed, globose, ca. 100 µm across. Conidia filiform, curved or spiral, 20-27 × 1.0 µm.

Chemistry: not studied.

Parasymbiont: none encountered.

Conservation status: XXXXX.

Bacidina egenula is easily recognized by the narrow spores and dark green epihymenium. The color of the hypothecium is variable, brown to colorless, even within a single collection. It is very similar in external aspect to Bacidia granosa, also common on carbonate rock, and, although rare on silicate rock, is likewise similar to Fellhanera silicis. While easily separated by spore type (rod-shaped and 3-sepate in the Bacidia and Fellhanera), spores in B. egenula are sometimes hard to find or see. Without spores, B. egenula can be recognized by the mostly colorless exciple and clumps of paraphyses with expanded, green sheathed end cells.

The distribution Bacidina egenula is poorly known, scattered collections at NY range from North Dakota south to Louisiana. It is rather common in the Ozarks, occurring on calcareous substrates, often in disturbed sites on bricks, concrete and mortar, twice on chert. Ekman (1996) cites a collection from the base of Ulmus americana.

Bacidina phacodes (Körber) Vezda
Folia Geobot. Phytotax. Praha 25: 432. 1991. Bacidia phacodes Körber, Parerga Lich. fasc. 2: 130. 1860.

Thallus on bark, of a few scattered, small, greenish areoles (goniocysts?). Apothecia whitish or discoloring(?) to pale buff, with disk usually slightly darker than margin, scattered, sessile, ± flat to convex, 0.2-0.3 mm across; margin even with disk or slightly raised, obscured in more convex apothecia. Exciple colorless, ca. 80 µm thick, of radiating hyphae with narrow lumina and end cell(s) enlarged and thick-walled. Hypothecium colorless, ca. 30 µm thick, of intertwined hyphae with some cells enlarged. Epihymenium colorless. Hymenium colorless, ca. 65-70 µm thick. Paraphyses unbranched, with tips not enlarged or capitate, to 5 µm across. Ascospores needle-like, 5-7-septate, 31-43 × 2 µm [3-7-septate, 29-45 × 1.5-2 µm (Purvis et al., 1992)]. Pycnidia not encountered.

Chemistry: not studied.

Parasymbiont: none encountered.

Conservation status: XXXXX.

There are three collections other with essentially colorless apothecial tissues as in B. phacodes or B. delicata (Leighton) V. Wirth & V_ zda, none seemingly conspecific with these or with each other, two on chert, one on duff under Juniperus. They are not adequate for full characterization. It is hoped additional material will be found allowing eventual disposition.

Bacidina phacodes, an otherwise European species, was not reported for North America by Ekman (1996). It differs from the closely related B. assulata in paler apothecia with apothecial tissues colorless in cross-section. The Ozark record consists of scattered apothecia on the edges of bark plates of an oak (red oak group) from Madison County, Arkansas. There are also two records further south in Arkansas, Jefferson and Prairie counties.

Bacidina sp. 2432
Thallus on decorticate wood, of small, tan (probably green when wet) rounded or isidioid granules (goniocysts). Apothecia dark brown, sometimes mottled with lighter brown, scattered to ± crowded, sessile, convex, with margin obscured from the beginning. Exciple washed with gray-brown in upper part (KOH+ purplish), orange-brown (KOH-) adjacent to hypothecium, otherwise colorless, outward with radiating hyphae with narrow lumina, with terminal cells not much enlarged. Hypothecium orange-brown (KOH-), of intertwined hyphae. Epihymenium colorless. Hymenium sparsely brownish streaked. Paraphyses unbranched, with tips not expanded or weakly capitate, ca. 3.5 µm across. Ascospores needle-like, 0-3-septate, 24-32 × 1.5-2 µm. Pycnidia pale to dark brown, semi-immersed, globose, ca. 100 µm across. Conidia needle-like, often broader toward one end, almost straight or slightly curved, 20-30 × 1-1.5 µm.

Chemistry: not studied.

Parasymbiont: none encountered.

This taxon seems very close to Bacidina egenuloidea S. Ekman, known from only two collection from southern Ohio, and may prove conspecific with it if more material is ever collected. It agrees with Bacidina egenuloidea in having an uncommon type of conidia (Ekman, 1996, type 3) but they are longer than reported by Ekman for B. egenuloidea. Also the hypothecium in B. egenuloidea is colorless not brown but if the variation encounterered in B. egenula is not unusual for this group in Bacidina, this difference may not be important. Bacidina egenuloidea differs in having a green epihymnium.

ILLINOIS. Union County: Pine Hills, edge of Otter Road, on old sycamore log, 14 Aug 1966, Skorepa 2432 (NY).

Bacidina sp. 17399
Thallus on silicate rock, greenish, of scattered to confluent, small, irregular areoles, occasionally becoming granular (goniocysts). Apothecia pale, ivory to pale buff, sometimes mottled with brown, or more orangish with disk buff-brown with paler orange-brown margin, scattered, sessile, ± flat to convex; margin concolorous or paler, even with disk or obscured in convex apothecia. Exciple colorless or weakly brownish tinted at rim (KOH-?), of radiating hyphae with rather large lumina and end cells enlarged. Hypothecium light yellow-brown (KOH-). Epihymenium colorless. Hymenium colorless. Paraphyses unbranched, not expanded at tips or capitate, to ca. 5 µm across. Ascospores needle-like, 0-3-septate, 21-26 × 1.5 µm. Pycnidia not found.

Chemistry: not studied.

Parasymbiont: none observed.

This taxon does not seem to match a described species but the available material is scanty. The silicate rock substrate and pale apothecia with brown hypothecium are the diagnostic characters.

MISSOURI. Iron County: St. Francis Mountains, Clark National Forest, along Co. Rd. N just N of Reynolds Co. line, 37° 40 N, 90° 47 W, on rhyolite pebble, 13 Oct 1993, Harris 31167-A (NY); Phelps County: Mark Twain National Forest, Roluf Spring Woodland restoration area, W of Forest Service Road 1516, ca. 4 mi WSW of Newburg, on underside of chert fragment in pasture, 11 Sep 1993, Ladd 17399 (Ladd).

Folia Geobot. Phytotax. 21: 200. 1986.

Crustose lichens with thin thallus, sessile dark apothecia, thalline margin absent, photobiont chlorococcoid, asci with an I+ apical dome including a darker tube, with 8 hyaline, fusiform, 1-3-septate spores, conidia short, fusiform or bottle-shaped.

The ± cellular exciple, ascus with a I+ dark tube in the apical dome and short, often bottle-shaped conidia suggest that the species below should be included in Fellhanera. However, most of the species of Fellhanera so far described grow on living leaves, suggesting that possibly some additional genera are needed to make sense of this group. The species are keyed under Bacidia.

Fellhanera silicisR. C. Harris & Ladd, sp. nov.

Aspectu vade similis Micarea erratica (Körber) Hertel, sat simils coloribus contexti apothecii et typo ascorum sed differt excipulo cellulis sat magnis subradiatis, ascosporis 3-septatis, 12-14 × 4-5 µm et microconidiis bacillaribus vel sublageniformibus, 5-6 × 1.5 µm.

Thallus on silicate rock, gray-green, olive-green or greenish brown, superficial, thin (80-100 µm), initially continuous, becoming cracked, without obvious prothallus (marginal region in Harris 31171 very thin, with a silvery cast). Apothecia dark brown to black, scattered, sessile, flat to weakly convex (ca. 150 µm thick), constricted to weakly constricted at base, 0.4-0.5 mm across when mature, with thin, concolorous margin, initially weakly raised, often becoming obscured with age. Exciple usually bicolor, greenish (KOH-, N+ red) inward, colorless outward, composed of weakly radiating, thick walled hyphae with large, irregular lumina (2-4 µm across). Hypothecium brown to chocolate brown, KOH-, N+ yellower. Epihymenium green (KOH-, N+ red). Hymenium colorless but appearing brownish streaked due to brownish pigment in some (moribund?) asci. Paraphyses unbranched or moderately branched, and somewhat anastomosed, often contorted, with tips irregularly clavate or not expanded, often with wall of apical cells greenish. Asci clavate. Ascospores colorless, ± fusiform, usually tapered at one end, 3-septate, slightly constricted at septa, 12-14 × 4-5 µm, without an obvious halo. Pycnidia ca. 100 µm, subglobose, ± immersed in thallus, with greenish wall. Microconidia bacillar to sublageniform, 5-6 × 1.5 µm. Buck 31800 has larger pycnidia, opening more broadly and larger bacillar conidia, 5-9 × 2-2.5 µm, forming short cirrhi.

Chemistry: no lichen substances detected (Buck 31986).

Parasymbiont: none encountered.

Conservation status: XXXXX.

In the field and under the dissecting microscope this lichen can pass for Micarea erratica which is widespread on non-calcareous rock in eastern North America. Further complicating hasty identifications, the green epithecium and brown hypothecium also mimic M. erratica. However, 3-septate vs. 0-septate ascospores and broad celled, weakly radiate, thick walled excipular hyphae vs. narrow, much branched and anastomosed, thin walled excipular hyphae embedded in a well developed gel matrix, readily separate it from M. erratica. Bacidia granosa (Tuck.) Zahlbr. with 3-septate ascospores is also quite similar but usually is confined to lime rich rocks and has the dark exciple continuous with the dark hypothecium, filiform conidia and "Bacidia type" ascus. The generic disposition is a problem. At first I was inclined to include it in Micarea as a 3-septate ascospore sibling of M. erratica. However, the excipular type and the weakly sublageniform conidia are more suggestive of Fellhanera. With such a very limited generic choice available at present this seems a reasonable disposition but as data accumulate a more definitive taxonomy may place it elsewhere.

Fellhanera silicis, as far as is now known, is an eastern American endemic centered in the Ozark region. It occurs on fine grained non-calcareous rock, rhyolite, fine grained sandstone and chert or quartz inclusions in lime rich situations. As far as one can tell with so few collections there seems to be a preference for wooded habitats unlike Micarea erratica which prefers open habitats. It may also tolerate more lime than M. erratica.

Selected specimens seen. ILLINOIS. Jackson County: Shawnee National Forest, Pomona Natural Bridge, ca. 37° 38'N, 89° 20'W, on sandstone, beech-maple woods, 15 Oct 1993, Buck 24233 (NY). KENTUCKY. Perry County: Daniel Boone National Forest, Old Field Branch of Leatherwood Creek, at NE end of KY 484, 3.25 mi NE of jct with KY 2022, 37° 17'49"N, 83° 28'46"W, ca. 325 m; mesic hardwoods along small stream, 6 Oct 2001, Buck 39902 (NY); Rowan County: Daniel Boone National Forest, bluffs at SE of Cave Run Lake at Claylick Boat Ramp, 38° 03'N, 83° 28'W, mixed hardwoods, 9 Oct 1995, Buck 28474 (NY). MISSOURI. Barry County: Roaring River State Park, Roaring River Hills Wild Area along CR F, 36° 34'50"N, 93° 50'00"W, dolomite glade with Juniperus, on chert, Buck 38830 (NY); Cape Girardeau County: Trail of Tears State Park, along W side of Mississipi River, ca. 9 mi NNE of downtown Cape Girardeau, SW1/4 sec. 11, T32N, R14E, on chert in roadbank, 29 Feb 1992, Ladd 16199 (Ladd); Carter County: Ozark National Scenic Riverways, Big Spring, trail from "Boil" to bridge over Big Spring Branch, 36° 57'N, 90° 59'30"W, on quartz in hardwoods over dolomite, 22 Sep 1990, Harris 25505 (NY); Dallas County: J. Haush farm, ca. 3.5 mi N of Elkland on hwy 38, at Webster County line, on chert, 11 Sep 1987, Summers 1894 (Ladd); Iron County: St. Francis Mountains, Clark National Forest, along Co. Rd. N just N of Reynolds Co. line, 37° 40'N, 90° 47'W, on rhyolite, 13 Oct 1993, Harris 31171 (NY); Oregon County: Mark Twain National Forest, McCormack Lake Recreation Area, lower portion of McCormack Hollow, 36° 49'N, 91° 21'W, on quartz, 17 Apr 1997, Buck 31936; Phelps County: Mark Twain National Forest, Bradford Branch woodland restoration area, E of Bradford Branch and S fo Ledbetter Hollow, ca. 4.5 mi WSW of Edgar Springs, sec. 4 & 5, T34N, R9W, on chert residuum on dolomite ledge in glade, 4 Oct 1993, Ladd 17637 (Ladd); St. Clair County: South-facing sandstone bluffs along N side of hwy 54, ca. 1.2 mi N of Blackjack, SW1/4 sec. 10, T36N, R26W, on shaded sandstone face at base of bluffs, 16 Jan 1993, Ladd 16974 (Ladd); Shannon County: MOFEP site 2, in Carrs Creek State Forest, ca. 2 mi S of hwy 106, N & E of Current River, sec. 22,23,26 T29N, R2W, on chert, Chadwell s.n. (Ladd); Taney County: Mark Twain National Forest, Hercules Glades Wilderness, from Hercules Tower to Pole Hollow, on chert pebbles, 18 Apr 1997, Buck 32031 (NY). OKLAHOMA. Adair County: Cookson Hills Wildlife Management Area, ca. 2 mi WSW of Bunch along N4610 Road, 35° 40'30"N, 94° 47'20"W, oak-hickory forest with small chert outcrop on E-facing slope, 1 Nov 2000, Buck 38616 (NY).

Fellhanera sp. 32111
Thallus on bark, gray, thin, continuous to very weakly areolate toward center, with poorly developed whitish prothallus. Apothecia sessile, constricted at base, soon convex, ; disk blackish brown, matt; margin ± soon excluded, grayish. Exciple cellular, colorless. Epihymenium colorless. Hymenium tinted purplish brown (KOH-). Hypothecium dark gray (KOH-). Paraphyses little or not expanded at tips. Ascospores 3-septate, ca. 11-12 × 4-4.5 µm. Pycnidia blackish, semi-immersed, globose, ca. 100 µm across. Conidia rod-shaped or weakly constricted in middle, 5.5-7 × 1.5-2 µm.

Chemistry: not studied.

Parasymbiont: none encountered.

This taxon is ± similar in aspect to some forms of Bacidia circumspecta which has a green epihymenium, hymenium often green streaked and exciple of radiating hyphae as well as a different type of ascus, spores and conidia. As yet known only from a single collection.

MISSOURI. St. Francois County: St. Francois State Park, Coonville Creek Wild Area, Mooner’s Hollow Trail, 37° 58'N, 90° 32'W, ca. 200 m, [on Carya], 19 Apr 1997, Buck 32111 (NY).

Fellhanera sp. 35950
Thallus on noncalcareous sandstone, olive-green, thick, of fused isidioid granules cracked into large polygonal areoles, to 1.0 mm across. Apothecia black, matt, scattered, sessile or slightly immersed among granules, initially flat but soon convex, 0.3-0.5 mm across; margin mostly concolorous to slightly paler, mostly obscured, even with disk or slightly raised. Exciple tinted green-black (KOH+ greener), with rim dark green, brown (KOH+ purplish) adjacent to hypothecium, of weakly radiating hyphae with ± large lumina. Hypothecium brown (KOH-). Epihymenium patchily blackish green (KOH+ greener). Hymenium greenish streaked (KOH+ greener). Paraphyses little expanded at tips or weakly clavate, to 5.5 µm across. Ascospores 3(-4)-septate, 15-17 × 3.5-5 µm. Pycnidia green, semi-immersed, ca. 100 µm across. Conidia fusiform, 4.5-5 × 1.5 µm.

Chemistry: not studied.

Parasymbiont: none encountered.

The thick thallus composed of ± isidioid granules is diagnostic. The apothecial pigmentation is very similar to F. silicis which has a thin thallus, longer spores and shorter conidia. This taxon is from just outside the Ozark ecoregion and could well occur in our area.

ILLINOIS. Saline County: Shawnee National Forest, Garden of the Gods Recreation Area, T.10S, R.7E., sect. 36, 37° 36'30"N, 88° 23'00"W, on shaded sandstone, 31 Jul 1999, Buck 35950 (NY).