11. Disterigma (KLOTZSCH) NIEDENZU Bot. Jahrb. Syst. 11: 160, 209 (1889).
-- Lectotype: Disterigma empetrifolium (H.B.K.) DRUDE.
Vaccinium sect. Disterigma KLOTZSCH, Linnaea 24: 57 (1851).
Vacciniopsis RUSBY, Bull. Torrey Bot. Cl. 20: 433 (1893). -- Type: Vaccinium ovata RUSBY
[=Disterigma ovatum (RUSBY) S. F. BLAKE].
Killipiella A. C. SMITH, J. Washington Acad. Sci. 33(8): 242 (1943). -- Type:
Killipiella styphelioides A. C. SMITH.

Reference: SMITH, A. C., The genera Sphyrospermum and Disterigma . Brittonia 1(4): 203--232 (1933). -- SLEUMER, H. O., Ericaceae americanae novae vel minus cognitae, I. Notizbl. Bot. Gart. Berlin-Dahlem 12 (112): 119--140 (1934). -- SMITH, A. C., Killipiella , a new Colombian genus of Vacciniaceae. J. Washington Acad. Sci. 33(8): 242--244 (1943). -- WILBUR, R. L., A synopsis of the genus Disterigma (Ericaceae: Vaccinieae) in Mexico and Central America with the description of two previously undescribed species. Bull. Torrey Bot. Cl. 119(3): 280--288 (1992).

Compact bushy to straggly, terrestrial or epiphyte shrubs. Leaves alternate, coriaceous, often congested, usually less than 3 cm long, margin entire or crenate, usually obscurely plinerved, short-petiolate. Inflorescence axillary, of solitary or 1--6-clustered, subsessile flowers, subtended by a few, minute, subcoriaceous bracts; pedicel short or lacking; bracteoles apical along pedicel, immediately subtending calyx hypanthium. Flowers (3-) 4 (-5)-merous, without odor; aestivation valvate (or calyx rarely imbricate); calyx obscurely articulate with the pedicel and embraced by the closely subtending bracteoles; hypanthium campanulate to short cylindric; lobes suberect; corolla subcylindric or campanulate-cylindric, (3-) 4--5-lobed; stamen equal, (5--6) 8, usually twice as many as the corolla lobes but rarely of the same number as the lobes; filaments distinct, ligulate, longer or shorter than anthers, lacking spurs; anthers dorsally attached near the base, membranous, lacking disintegration tissue; thecae smooth; tubules (1-) 2 and dehiscing by elongate, elliptical, introrse clefts or subterminal pores; pollen lacking viscin threads; ovary inferior, (3-) 4 (-5)-locular; style filiform and about as long as the corolla; stigma truncate; nectariferous disc fleshy, annular-pulvinate. Fruit a berry, thick-walled, coriaceous, blue-black or translucent white; seeds sometimes mucilaginous.

Disterigma is a small genus of about 35 species ranging from the highlands of Guatemala south to Bolivia and east to Guyana.


Key to Species of Disterigma
1a.
Stamen 5.
2a.
Flowers surrounded by a series of numerous, persistent, ovate to ovate-lanceolate bracts to 7 mm long; calyx lobes narrowly lanceolate, ca 3.5 mm long; bracteoles ovate-lanceolate, long-acuminate, ca 7 mm long; S Bolívar-Chimborazo provinces (ca 2% S latitude) and south
............................................................................................D. pentandrum
2b.
Flowers surrounded by a series of few, caducous, ovate bracts to 2 mm long; calyx lobes deltate, ca 1 mm long; bracteoles oblong to lanceolate, obtuse to acute, ca 1--2 mm long; Imbabura to S Bolívar provinces (but N of 2% S latitude)
............................................................................................D. rimbachii
1b.
Stamen 8 or 10, double the number of corolla lobes.
3a.
Anther tubules fused into 1
...........................................................................................D. utleyorum
3b.
Anther tubules 2, separate not fused.
4a.
Corolla campanulate-rotate.
5a.
Corolla 3.6--6 mm long, white to greenish.
6a.
Corolla 5--6 mm long, white; leaves 10--15 x 5--8 mm, the apex obtuse or rounded
..............................................................D. campii
6b.
Corolla 3.6--5 mm long, green; leaves 3.8-7.5 x 1.7--5 mm, the apex acuminate to short-cuspidate
..............................................................D. microphyllum
5b.
Corolla 7--10 mm long, red to greenish-red.
7a.
Leaves elliptic-oblong, 6.5--9 x 3--4 mm, the apex rounded, the margin entire; twigs pilose-strigose; bracteoles 1.5--2 mm long; calyx hypanthium sharply 4-angled, 1.5--2 mm long, the lobes 1.5--2 mm long; staminal filaments 2--2.5 mm long
..............................................................D. dumontii
7b.
Leaves ovate-oblong, 5--11 x 1.5--5 mm, the apex acute to subacute, the margin crenate; twigs short-pilose or hispidulous; bracteoles 3.5--5 mm long; calyx hypanthium terete, 2--2.7 mm long, the lobes 2.5--3 mm long; staminal filaments 3.5--5 mm long
..............................................................D. codonanthum
4b.
Corolla cylindric to cylindric-urceolate.
8a.
Apex of leaves acuminate or conspicuously cuspidate.
9a.
Corolla 4.5--8 mm long; leaves 0.5--1.2 x 0.3--0.7 cm; bracteoles 2--3 mm long, surrounding only the lower half of the calyx hypanthium or sometimes up to the tips of the calyx lobes
..............................................................D. acuminatum
9b.
Corolla (6-) 8--11 mm long; leaves 1.2--2.5 x 0.5--1.6 cm; bracteoles 5--7 mm long, completely surrounding and concealng the entire calyx and lower half of the corolla at anthesis
..............................................................D. cryptocalyx
8b.
Apex of leaves rounded, obtuse or acute, (rarely in D. alaternoides acuminate but then > 1 cm broad).
10a.
Corolla 3.5--6 mm long.
11a.
Leaves linear-oblong to elliptic-oblong, 3.3--10 x 0.7--2 mm; calyx lobes tufted-setose at tips; corolla red, 5--6 mm long; stamen exserted at anthesis
.....................................................D. agathosmoides
11b.
Leaves elliptic to ovate-subrotund, 5--10 x 3--5 mm; calyx lobes glabrous; corolla white, 3.5--4.3 mm long; stamen inserted at anthesis.
12a.
Leaves narrowly elliptic, 8--10 mm long; bracteoles enclosing only calyx hypanthium; corolla cylindric-urceolate, distally inflated
..........................................D. micranthum
12b.
Leaves ovate-subrotund, 4--5.5 mm long; bracteoles enclosing all the calyx and the lower half of the corolla; corolla narrowly cylindric, not inflated
.........................................D. noyesiae
10b.
Corolla 6 mm long or more.
13a.
Corolla densely and persistently puberulent to pilose.
14a.
Leaves ovate, 0.6--1.3 x 0.4--0.6 cm; corolla 11--13 mm long, red
.........................................D. balslevii
14b.
Leaves elliptic, (1.1-) 1.5--2.2 x 0.8--1.5 cm; corolla ca 9--9.5 mm long, white
.........................................D. leucanthum
13b.
Corolla glabrous (or essentially so).
15a.
Calyx 7.3--8 mm long, the lobes obovate-elliptic, apiculate, narrowly imbricate, ca 5 mm long
.........................................D. stereophyllum
15b.
Calyx < 5 mm long, the lobes triangular-deltate, separate, ca 2.5 mm long or less.
16a.
Leaves mostly greater than 5 mm broad.
17a.
Leaf apex acute or very rarely slightly acuminate
...................D. alaternoides
17b.
Leaf apex rounded.
18a.
Flowers sessile; corolla 9--11 mm long; calyx lobes 2.5--3 mm long, ciliate
..........D. ecuadorense
18b.
Flowers with pedicel to ca 2 mm long; corolla 4.5--6 (-8) mm long; calyx lobes 1.5--2 mm long, not ciliate
..........D. humboldtii
16b.
Leaves equal to or mostly less than 5 mm broad.
19a.
Leaves ovate, elliptic, or rarely orbicular, 4--7 (-9) mm broad; corolla white to pinkish
...................D. humboldtii
19b.
Leaves linear to narrowly elliptic, or oblong- to elliptic-lanceolate, 1.3--5 mm broad; corolla red, white, or pale yellowish-green.
20a.
Corolla red; leaves 4.5--12 mm long; plants growing from montane cloud forest to superpáramo, at 2865--4350 m altitude
..........D. empetrifolium
20b.
Corolla white to pale yellowish-green, often with pink or red lobes; leaves (0.8-) 13--20 mm long; plants growing in pluvial forest (in Ecuador), at 650--750 m altitude
..........D. pseudokillipiella