Pseudohydrosme Engl.

CATE Araceae, 17 Dec 2011. araceae.e-monocot.org

General Description

HABIT : large, seasonally dormant herbs, tuber subglobose, subterranean, with annular leaf scars, growing continuously and not renewed with each growing period. LEAF : solitary, large. PETIOLE : long, aculeate, sheath very short. BLADE : trisect, primary divisions pinnatifid or bipinnatifid to pinnatisect, ultimate (distal) lobes mostly truncate to shallowly bifid, sessile to decurrent, proximal lobes acute-acuminate; primary lateral veins of ultimate lobes pinnate, forming irregular submarginal collective vein or running into margin, higher order venation reticulate. INFLORESCENCE : solitary, appearing before leaf. PEDUNCLE : aculeate, very short, much shorter than petiole. SPATHE : large, somewhat resembling the horn of a euphonium, unconstricted, bright yellow, dark purple within and at mouth of tube, tube convolute, fleshy, obconic, blade very broad, thinner, with flaring, auriculate margins, fornicate. SPADIX : very short, sessile, female zone subcylindric, male zone cylindric, obtuse, subequal to or longer than female, fertile to apex ( P. gabunensis) or with appendix covered with sterile flowers ( P. buettneri). FLOWERS : unisexual, perigone absent. MALE FLOWER : 2-5-androus, stamens free, subprismatic, compressed, anthers sessile, connective thick, broad, overtopping thecae, thecae oblong, long, lateral, dehiscing by apical pore. POLLEN : extruded in strands, inaperturate, ellipsoid-oblong, very large (mean 106 µm., range 93-114 µm.), exine psilate to slightly scabrous. STERILE MALE FLOWERS : composed of subprismatic, free staminodes. FEMALE FLOWER : ovary globose to broadly ellipsoid, sometimes compressed, 2(-3)-locular, ovules 1 per locule, anatropous, funicle short, placenta axile at base of septum, style attenuate to cylindric, narrower than ovary, stigma thick, 2(-3)-lobed, concave centrally. BERRY : unknown. SEED : unknown.

Habitat

Tropical humid forest; geophytes on forest floor.

Distribution

WC. Trop. Africa.

Diagnostic

Large, seasonally dormant geophyte; leaf solitary; petiole prickly; leaf blade dracontioid, ultimate leaf lobes mostly truncate to shallowly bifid, submarginal collective vein irregular or absent, fine venation reticulate; spathe large, lower part a convolute tube, upper part very broad with flaring auricled margins; spadix fertile to apex or with terminal appendix of staminodes; flowers unisexual, perigone absent. Differs from Anchomanes in very short peduncle and 2-locular ovary.