10. Ceratostema JUSSIEU Gen. Pl. 163 (1789). -- Type: Ceratostema peruvianum GMELIN.

Englerodoxa HOEROLD, Bot. Jahrb. Syst. 42: 310 (1909). -- Type: Englerodoxa alata HOEROLD.
Periclesia A. C. SMITH, Contr. U.S. Natl. Herb. 28(2): 357 (1932). -- Type: Periclesia flexuosa
A. C. SMITH.

References: SMITH, A. C., Plants collected in Ecuador by W. H. Camp- Vacciniaceae. Mem. New York Bot. Gard. 8(1): 41--85 (1952). -- LUTEYN, J. L., New species of Ceratostema (Ericaceae: Vaccinieae) from the northern Andes. J. Arnold Arb. 67: 485--492 (1986).

Terrestrial or epiphytic shrubs to 3.5 m tall, sometimes scandent, often arising from lignotubers. Leaves alternate, coriaceous, pinnate or plinerved, petiolate. Inflorescences axillary, fasciculate, racemose, or flowers solitary; floral bract small to large and showy. Flowers (4-) 5 (-6)-merous, without odor; aestivation valvate; calyx articulate with the pedicel (obscurely so or continuous in C. loranthiflorum ); hypanthium obconical or campanulate, terete, angled to costate, or winged; limb suberect or spreading; lobes elongate-triangular or triangular, often distinctly veined; corolla thick-carnose, often large, subcylindric but often ventricose at base, terete or more commonly bluntly angled, usually deeply lobed, the lobes usually narrowly-elongate; stamen (8-) 10, equal or more commonly alternately slightly unequal, nearly as long as corolla or appearing exserted when corolla lobes become reflexed; filaments distinct or connate, equal or alternately slightly unequal, basifixed, lacking spurs; anthers equal or alternately slightly unequal, lacking disintegration tissue; thecae often alternately slightly unequal, usually strongly granular (papillose); tubules often alternately slightly unequal, much thinner and often 2--5 times longer, rarely equal to or shorter, than the thecae, flexible, distinct to base to connate nearly to apex, dehiscing by short, oblique clefts or nearly terminal pores, these sometimes flaring; pollen lacking viscin threads; ovary inferior; style filiform, as long as corolla or slightly exserted; stigma truncate. Fruit a spherical, many-seeded, dark blue-black berry.

The genus Ceratostema contains ca 32 species ranging from Venezuela to N Peru. Twenty-six species are endemic to eastern (Oriente) Ecuador, 1 is endemic to the Guayana Highland of Venezuela, and 3 to northern Peru. Two species are common to southern Colombia and eastern (Oriente) Ecuador. [NOTE: Unless otherwise stated, measurements in this genus are given for dried material at anthesis, because considerable elongation of pedicels and calyces may occur post-anthesis, whereas considerable shrinkage occurs in the corollas upon drying.]


Key to Species of Ceratostema
1a.
Leaves basally attenuate, acute, or rounded, rarely subcordate but not amplexicaul.
2a.
Calyx limb very conspicuous, the lobes at least 10 mm long.
3a.
Calyx hypanthium terete, neither costate nor winged.
4a.
Flowers 4-merous; leaf blade 3.5--6 x 1.2--1.8 cm; flowers in 3--4-flowered racemes; corolla lobes 20--21 mm long; staminal filaments connate
.....................................................................C. flexuosum
4b.
Flowers 5-merous; leaf blade 9--13 x 3--5 cm; flowers in fascicles of 4--6; corolla lobes 4--9 mm long; staminal filaments distinct
.....................................................................C. fasciculatum
3b.
Calyx hypanthium 10-costate or 5-winged.
5a.
Calyx hypanthium 10-costate.
6a.
Bracteoles located at apex of the pedicel, 13--20 mm long, clasping and concealing the calyx hypanthium at anthesis; rachis < 1 cm long; plants short-pilose all over
............................................................C. bracteolatum
6b.
Bracteoles located at or below middle of pedicel, ca. 4 mm long, not clasping calyx; rachis 6--8 cm long; plants with glabrous or puberulent habit
............................................................C. calycinum
5b.
Calyx hypanthium clearly 5-winged.
7a.
Leaves plinerved, (2-) 3.5--9.5 cm broad; rachis (2-) 5.5--13 (-22) cm long; floral bract 8--20 mm long; bracteoles apical; calyx (25-) 35--45 mm long, the lobes (10-) 15--21 mm long; staminal filaments connate
............................................................C. reginaldii
7b.
Leaves pinnately-nerved, (0.6-) 1--2.5 (-3) cm broad; rachis (0.3-) 0.6--4 cm long; floral bract 2--7 mm long; bracteoles basal; calyx 10--35 mm long, the lobes 7--25 mm long; staminal filaments distinct.
8a.
Calyx 28--35 mm long at anthesis, the lobes 19--25 mm long; rachis 1--1.5 (-4) cm long
...................................................C. megalobum
8b.
Calyx 10--22 mm long at anthesis, the lobes 7--15 mm long; rachis 0.3--1.1 cm long.
9a.
Leaves beneath and flowers (pedicel, calyx, corolla) short-pilose; corolla 31--45 mm long; floral bract linear-lanceolate to narrowly triangular, acuminate, 4--7 mm long
..........................................C. lanceolatum
9b.
Leaves and flowers glabrous; corolla 21--28 mm long; floral bract deltate, acute, 2--3 mm long
..........................................C. oellgaardii
2b.
Calyx limb comparatively inconspicuous, the lobes 1--8 (-10) mm long.
10a.
Calyx continuous with the pedicel; corolla 15--20 mm long
..................................................................................C. loranthiflorum
10b.
Calyx articulate with the pedicel; corolla 26 mm long or more.
11a.
Calyx and corolla lobes both provided with circular, concave, black glands at their bases.
12a.
Leaves concave or margins at least inrolled, 1--2.2 cm long, pilose beneath; rachis 0.1--0.2 cm long; floral bract without circular gland at base
............................................................C. madisoni
12b.
Leaves flat, 2--12 cm long, glabrous beneath; rachis 0.8--7 cm long; floral bract with or without a circular gland at its base.
13a.
Leaves 2--4 x 1--1.7 cm, the apex obtuse to bluntly acute; inflorescence 4-flowered; rachis 0.8--0.9 cm long; floral bract with basal, circular gland; pedicel 9--13 mm long; corolla 29--30 mm long
...................................................C. glans
13b.
Leaves 6--12 x 2--5.3 cm, the apex sharply acuminate; inflorescence (2-) 5--22-flowered; rachis 0.8--7 cm long; floral bract without basal, circular gland; pedicel 13--27 mm long; corolla 35--48 mm long
...................................................C. ventricosum
11b.
Calyx and corolla lobes normally without basal glands (or glands only present on either calyx or corolla but not both).
14a.
Leaf venation plinerved.
15a.
Rachis 9--16.5 (-25) cm long; leaves 12--16 x 2--2.5 cm, falcate; calyx hypanthium bluntly 5-angled, the lobes 5.5--8 mm long, without marginal glandular fimbriae
..................................................C. pedunculatum
15b.
Rachis 0.8--8.5 cm long; leaves 2.5--17 x 1.5--6 cm, not falcate; calyx hypanthium terete, the lobes 1--6 mm long, with marginal glandular fimbriae.
16a.
Calyx lobes apiculate, scarcely 1 mm long, marginally eglandular; floral bract 1 mm long, marginally eglandular; leaves 10--17 cm long
..........................................C. prietoi
16b.
Calyx lobes conspicuous, 2--6 mm long, marginally glandular-fimbriate; floral bract 1.5--4 mm long, marginally glandular-fimbriate; leaves 2.5--12 cm long.
17a.
Leaves 2.5--5 cm long, the margin weakly serrate-crenate; calyx 10--15 mm long, the lobes 3--6 mm long; corolla (40-) 55--60 mm long, basally not ventricose; rachis 3--6 cm long, pedunculate (i.e., flowering towards tip only)
.................................C. nubigenum
17b.
Leaves 6--12 cm long, the margin entire; calyx 5--7 mm long, the lobes 2--3.5 mm long; corolla 35--48 mm long, basally ventricose; rachis 0.8--7 cm long, flowering along entire length
...................................C. ventricosum
14b.
Leaf venation pinnate.
18a.
Leaves 7--13.5 cm long, the base acute, the apex gradually acuminate, the margin flat; staminal filaments free to weakly connate
.................................................C. charianthum
18b.
Leaves 2--5 (-8.5) cm long, the base broadly cuneate to rounded (sometimes subcordate), the apex acute to rounded (rarely acuminate), the margin flat to revolute; staminal filaments distinct.
19a.
Calyx lobes apiculate, ca 1--2 mm long; leaves revolute and usually marginally serrate or crenulate
..........................................C. alatum
19b.
Calyx lobes conspicuous, 5--8 (-10) mm long; leaves flat to slightly recurved, the margin entire
..........................................C. campii
1b.
Leaves basally conspicuously cordate and usually amplexicual.
20a.
Calyx limb very conspicuous, the lobes 9 mm long or more.
21a.
Calyx hypanthium terete; bracteoles located at apex of pedicel; rachis, pedicel, calyx, and corolla with glandular-tipped hairs
...................................................................................C. pensile
21b.
Calyx hypanthium 5-winged or 10-costate; bracteoles at or below middle of pedicel; floral pubescence when present of eglandular hairs.
22a.
Calyx hypanthium 5-winged; bracteoles ca 1 mm long.
23a.
Calyx lobes 9--10 mm long, only the margins sparsely ciliate; leaves glabrous
............................................................C. auriculatum
23b.
Calyx lobes 20--21 mm long, densely short-pilose within and without; leaves densely and shortly floccose-tomentose beneath
............................................................C. macbrydiorum
22b.
Calyx hypanthium 10-costate; bracteoles (6-) 15--35 mm long.
24a.
Floral bracts (45-) 60--70 mm long, persistent and covering the flowers at anthesis; bracteoles 35--45 mm long; pedicel 10--12 mm long
............................................................C. megabracteatum
24b.
Floral bracts (7-) 10--18 (-35) mm long, caducous, rarely persistent; bracteoles (6-) 15--25 mm long; pedicel 15--40 mm long
............................................................C. peruvianum
20b.
Calyx limb comparatively inconspicuous, the lobes 1--7 mm long.
25a.
Floral bracts 40--70 mm long, persistent, covering the flowers at anthesis
..............................................................................C. nodosum
25b.
Floral bracts 2--8 mm long, usually caducous, much shorter than the flowers at anthesis.
26a.
Inflorescence fasciculate, densely hirsute
.....................................................................C. lanigerum
26b.
Inflorescence racemose, short-pilose or glabrous.
27a.
Leaves broadly ovate-orbicular, > 9 cm broad, the apex cuspidate to shortly and sharply acute; calyx hypanthium 5-winged, the lobes apiculate, < 1 mm long; corolla winged over entire length
............................................................C. cutucuensis
27b.
Leaves ovate-elliptic, < 9 cm broad, the apex obtuse to acuminate; calyx hypanthium essentially terete to conspicuously 10-costate, the lobes 2--7 mm long; corolla terete not winged.
28a.
Corolla 27--38 mm long; calyx hypanthium cylindric, terete to inconspicuously 10-costate; rachis 0.9--4 cm long, with the pedicel and calyx rather thin and delicate in appearance; inflorescence 3--8-flowered; floral bracts ca 2--3 mm long, persistent after anthesis; 450--1000 m altitude; south of Baeza (Napo Prov.)
...................................................C. silvicola
28b.
Corolla 43--50 mm long; calyx hypanthium turbinate, conspicuously 10-costate; rachis 5--13 cm long, with the pedicel and calyx thick and coarse in appearance; inflorescence 5--25-flowered; floral bracts (2-) 5--8 mm long, deciduous; 1350--1900 m altitude; north of Baeza (Napo Prov.)
...................................................C. amplexicaule