James L. Luteyn and Paola Pedraza-Peñalosa
The New York Botanical Garden
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Ceratostema is a neotropical
genus of about 33 species, ranging from southern Colombia to northern Peru,
with a disjunct species in Guyana. The genus was first described
by A. L. de Jussieu in 1789,
the name referring to the long "horned stamen" (the "horns" are the
long anther tubules). It was last treated in its entirety by A. C.
Smith (1952), who gave a brief discussion and a key to the 16 species then
recognized. Ceratostema is characterized by: calyx articulate
with the pedicel (articulation obscure in one species); corolla large
and usually conspicuously ventricose basally, deeply lobed, the lobes usually
very long and narrow; and stamens with the filaments distinct or
connate, the thecae strongly granular (or papillate), and the tubules very
long and thin, dehiscing by short, oblique clefts. Ceratostema is most closely related to Semiramisia Klotzsch (Luteyn, 1984). |
CERATOSTEMA Jussieu, Gen. pl. 163. 1789;
Smith, A. C., Mem. New York Bot. Gard. 8: 41-85. 1952; Luteyn,
J. L., J. Arnold Arb. 67: 485-492. 1986; Luteyn, J. L., Fl.
Ecuador 54: 210-253. 1996. Type: Ceratostema peruvianum Gmelin.
Englerodoxa Hoerold, Bot. Jahrb. Syst. 42: 310. 1909. Type: Englerodoxa alata Hoerold (= Ceratostema alatum (Hoerold) Sleumer).Periclesia A. C. Smith, Contr. U.S. Natl. Herb. 28: 357. 1932. Type: Periclesia flexuosa A. C. Smith (=Ceratostema flexuosum (A. C. Smith) Macbride).
Terrestrial or epiphytic shrubs to 3.5
m tall, sometimes scandent, often arising from lignotubers. Leaves
alternate, petiolate, coriaceous, plinerved or pinnately veined.
Inflorescences axillary, solitary, fasciculate, or racemose; floral
bract small to large and showy; bracteoles two. Flowers pedicellate,
(4-)5(-6)-merous, without
odor; aestivation valvate; calyx articulate with the pedicel
(obscurely so 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; stamens (8-)10,
equal or alternately slightly unequal, nearly as long as corolla, slightly
exserted or appearing exserted when corolla lobes become reflexed, lacking
spurs; filaments distinct or connate, equal or
lternately slightly unequal, attached to the anther dorsally near
its base; anthers 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 berry, usually dark
blue-black but rarely translucent, greenish-white.
Key to Neotropical Species Back to Top
1. Leaves basally attenuate, acute, obtuse, or rounded, rarely
subcordate but not amplexicaul ............................................................ 2
1. Leaves basally conspicuously cordate and usually amplexicual ............. 22
2. Calyx limb very conspicuous, the lobes at least 10 mm long .................. 3
2. Calyx limb comparatively inconspicuous, the lobes 1-8(-10) mm long
........................................................................................................... 10
3. Calyx hypanthium terete, neither costate nor winged ............................. 4
3. Calyx hypanthium 10-costate or 5-winged ........................................... 5
4. 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
4. 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
5. Calyx hypanthium 10-costate ............................................................... 6
5. Calyx hypanthium clearly 5-winged ...................................................... 7
6. 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
6. 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
7. 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
7. 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
........................................................................................................... 8
8. Calyx 28-35 mm long at anthesis, the lobes 19-25 mm long; rachis 1-
1.5(-4) cm long .............................................................. C. megalobum
8. Calyx 10-22 mm long at anthesis, the lobes 7-15 mm long; rachis
0.3-1.1 cm long .................................................................................. 9
9. 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
9. Leaves and flowers glabrous; corolla 21-28 mm long; floral bract
deltate, acute, 2-3 mm long ............................................... C. oellgaardii
10. Calyx continuous with the pedicel; corolla 15-20 mm long
................................................................................... C. loranthiflorum
10. Calyx articulate with the pedicel; corolla 26 mm long or more ............ 11
11. Calyx and corolla lobes both provided with circular, ± concave,
black glands at their bases ................................................................. 12
11. Calyx and corolla lobes normally without basal glands (or glands
only present on either calyx or corolla but not both) ........................... 14
12. 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. madisonii
12. 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 ......................... 13
13. 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
13. 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
14. Leaf venation plinerved ...................................................................... 15
14. Leaf venation pinnate ......................................................................... 19
15. 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
15. Rachis 0(flowers solitary)-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 ................................................................. 16
16. Calyx lobes apiculate, scarcely 1 mm long; floral bract 1 mm long;
leaves 10-17 cm long ............................................................. C. prietoi
16. Calyx lobes conspicuous, 2-6 mm long; floral bract (0.5-)1.5-4 mm
long; leaves 1.5-12 cm long ............................................................... 17
17. Flowers solitary in leaf axils; corolla 28-30 mm long; Peru ...... C. rauhii
17. Flowers racemose; corolla 35-60 mm long; Ecuador ........................ 18
18. 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
18. 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
19. Leaves 7--13.5 cm long, the base acute, the apex gradually
acuminate, the margin flat; staminal filaments free to weakly
connate ......................................................................... C. charianthum
19. Leaves 2-5(-8.5) cm long, the base broadly cuneate to rounded
(sometimes subcordate), the apex acute to rounded (acuminate in C.
glandulifera), the margin flat to revolute; staminal filaments
distinct .............................................................................................. 20
20. Calyx lobes apiculate, ca 1-2 mm long; leaves revolute and usually
marginally serrate or crenulate ................................................ C. alatum
20. Calyx lobes conspicuous, 2.5-8(-10) mm long; leaves flat to
slightly recurved (or bullate), the margin entire .................................... 22
21. Calyx and corolla covered by gland-tipped hairs; Venezuela ....
....................................................................................... C. glandulifera
21. Calyx and corolla short-pilose, but not with gland-tipped hairs;
Ecuador ................................................................................. C. campii
22. Calyx limb very conspicuous, the lobes 9 mm long or more ................ 23
22. Calyx limb comparatively inconspicuous, the lobes 1-7 mm long ........ 28
23. Calyx hypanthium terete ................................................................... 24
23. Calyx hypanthium 5-winged or 10-costate; bracteoles at or below
middle of pedicel; floral pubescence when present of eglandular
hairs ................................................................................................ 25
24. Bracteoles located at apex of pedicel, up to 17 mm long; leaves
essentially glabrous beneath; calyx lobes 10 mm long; staminal
filaments connate .................................................................. C. pensile
24. Bracteoles located at middle of pedicel, 5-8 mm long; leaves
usually densely soft-pilose beneath; calyx lobes 10-17 mm long;
staminal filaments distinct ................................................... C. callistum
25. Calyx hypanthium 5-winged; bracteoles ca 1 mm long ..................... 26
25. Calyx hypanthium 10-costate; bracteoles (6-)15-35 mm long .......... 27
26. Calyx lobes 9-10 mm long, only the margins sparsely ciliate; leaves
glabrous ....................................................................... C. auriculatum
26. Calyx lobes 20-21 mm long, densely short-pilose within and without;
leaves densely and shortly floccose-tomentose beneath .........
................................................................................ C. macbrydiorum
27. 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
27. Floral bracts (7-)10-18(-35) mm long, caducous, rarely persistent;
bracteoles (6-)15-25 mm long; pedicel 15-40 mm long ......
................................................................................... C. peruvianum
28. Floral bracts 40-70 mm long, persistent, covering the flowers at
anthesis ........................................................................... C. nodosum
28. Floral bracts 2-8 mm long, usually caducous, much shorter than the
flowers at anthesis .......................................................................... 29
29. Inflorescence fasciculate, densely hirsute ......................... C. lanigerum
29. Inflorescence racemose, short-pilose or glabrous ............................ 30
30. 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. cutucuënse
30. 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 ................................. 31
31. Leaves bullate, apically long-acuminate, basally auriculate with
the lobes well separated, not imbricate ............................ C. ferreyrae
31. Leaves flat, apically obtuse or acute, basally auriculate-clasping
with the lobes conspicuously imbricate ........................................... 32
32. 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
32. 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
This is an electrocnic version of Luteyn, 1984, 1986a, and 1996b, and other unpublished notes.