21. Anthopterus HOOKER Icon. Pl. 3: pl. 243. 1840. -- Type: Anthopterus racemosus

HOOKER.

Low shrubs or small trees, sometimes epiphytes. Leaves alternate, subopposite, or verticillate, coriaceous, margin entire, pinnate or plinerved. Inflorescence axillary, racemose, with several to many flowers; floral bract to 20 mm long but usually small and inconspicuous. Flowers 5-merous, without odor; aestivation valvate; calyx continuous with pedicel; hypanthium broadening distally and winged; limb suberect; lobes ovate to deltate; corolla subcylindric, cylindric-urceolate or subglobose, narrowly to broadly 5-winged, the lobes triangular, subacute to long-acuminate; stamen 10, essentially equal, nearly as long as the corolla; filaments equal, distinct or basally slightly connate, shorter than anthers, lacking spurs; anthers dorsifixed, membranous, lacking distintegration tissue; thecae smooth; tubules longer than the thecae, dehiscing by short to elongate clefts; pollen lacking viscin threads; ovary inferior; stigma truncate; style filiform, about as long as the corolla; nectariferous disc annular or cupuliform. Fruit a berry.

Anthopterus is a genus of 11 species ranging from southeastern Panama to northeastern Peru. There are few collections of any of the species and hence the range of variation within the genus is unknown. Anthopterus is closely related to Thibaudia and Themistoclesia , but is traditionally separated from them by the conspicuously winged calyx and corolla of the former genus.

1a.

Leaves subopposite to verticillate (rarely alternate), the base of the lamina beneath without a circular gland on each side of midrib; corolla wings usually broadest towards apex (except A. verticillatus ); corolla lobes not so strongly reflexed as to expose stamen; corolla color reddish-orange at base with a green band distally and white limb and lobes; western Ecuador.

2a.

Leaves alternate, up to 4 (-11) cm broad; rachis without flowers near base; floral bracts 2--5 mm long, much shorter than the 8--23 mm long pedicel

............................................................................................A. wardii

2b.

Leaves subopposite, opposite, or verticillate, 3.5--10 cm broad; rachis bearing flowers along entire length; floral bracts 12--20 mm long, equal to or longer than the 3--15 mm long pedicel.

3a.

Floral bracts broadly imbricate, appressed, 10--13 mm broad, concealing the rachis, pedicel, and most of each flower at anthesis

...................................................................................A. verticillatus

3b.

Floral bracts well-spaced, spreading, 4--6 mm broad, not concealing the rachis, pedicel, or flowers at anthsis.

4a.

Stem, rachises, pedicel, calyces, and sometimes corollas puberulent; corolla obviously winged, broadest well above the middle; calyx wings obvious, narrow and sharp; lowlands of Esmeraldas Prov., 800--1350 m

.........................................................................A. cuneatus

4b.

Stem, rachises, pedicel, calyces and corollas glabrous, although calyces rarely puberulent; corolla narrowly and obscurely winged, broadest at or below the middle; calyx wings relatively inconspicuous, blunt; Pichincha Prov., 2200--2300 m

........................................................................A. ecuadorensis

1b.

Leaves strictly alternate, the base of the lamina beneath with a circular gland on each side of midrib; corolla wings broadest at base; corolla lobes so strongly reflexed that they expose stamen; corolla color whitish- or yellowish-green; usually Oriente lowlands.

5a.

Leaves linear, strongly revolute and incurved over entire length, less than 15 mm broad, the venation pinnate; corolla 7--9 mm long

...........................................................................................A. revolutus

5b.

Leaves ovate, elliptic, to oblong-elliptic, flat to only weakly incurved, greater than 10 mm broad, the venation plinerved; corolla 7--20 mm long.

6a.

Inflorescence 5--12-flowered; rachis 5--11 cm long; pedicel 6--12 mm long; corolla 7--9 mm long, the lobes 2--3 mm long

................................................................................A. schultzeae

6b.

Inflorescence 10--22 flowered; rachis 4.5--21 cm long; pedicel 14--40 mm long; corolla 13--20 mm long, the lobes 5--9 mm long.

7a.

Leaves broadly elliptic, 4--10 cm broad, the apex rounded, or obtuse to bluntly acute; pedicel (16-) 30--40 mm long; corolla 18--20 mm long; staminal filaments glabrous

.....................................................................A. gentryi

7b.

Leaves ovate, 1.5--4 cm broad, the apex acuminate; pedicel 14--22 mm long; corolla 13--15 mm long; staminal filaments pilose

.....................................................................A. molaui