HABIT : robust to slender evergreen herbs, solitary to clump-forming, rhizome subterranean, horizontal or vertical, spongy. LEAVES : few, basal, ± erect. PETIOLE : long, spongy, sheathed only at base, smooth or scabrid-verrucose, sometimes angled, often variegated, apical geniculum absent or only very weakly developed, sheath long to short. BLADE : deeply sagittate or subtripartite to hastate, posterior divisions usually longer than anterior division, rarely blade lanceolate-linear and lacking posterior divisions (U. wurdackii); basal ribs well-developed, primary lateral veins of both anterior and posterior divisions pinnate, long-arcuate towards division apex and running into marginal vein, higher order venation reticulate. INFLORESCENCE : solitary, rarely 2 in each floral sympodium. PEDUNCLE : equal to or longer than leaf, similar in appearance to petiole. SPATHE : erect, persistent, convolute below, gaping above, apically long-acuminate, usually spirally twisted, sometimes flattened. SPADIX : shortly stipitate or sessile, usually much shorter than spathe, cylindric to subcylindric, obtuse. FLOWERS : bisexual, perigoniate; tepals 4-6, fornicate. STAMENS : 4-6, filaments free, broadish, a little compressed, connective slender, thecae ellipsoid, dehiscing by apical slit. POLLEN : monosulcate, ellipsoid, medium-sized (mean 26 µm., range 25-28 µm.), exine subreticulate, subrugulate to reticulate, apertural exine psilate. GYNOECIUM : ovoid, ovary 1-2-locular, ovules (1-)2-4 or more per locule, anatropous, placenta axile in 2-locular ovaries, basal in 1-locular ovaries, stylar region a little narrower than ovary, stigma broad, circular, discoid. BERRY : obovoid, 1-5(-8)-seeded, green to greenish yellow. SEED : curved, testa hard, brown, thickish, strongly warty, or spiny or crested, embryo curved, endosperm present but only as a very thin layer about 2 cells thick.
Slender to robust, evergreen helophytes with vertical or horizontal rhizome; petiole smooth to scabrid, never prickled; leaf blades deeply sagittate, trisect to hastate, very rarely linear-lanceolate, fine venation reticulate; flowers bisexual, perigoniate; seed curved, testa warty, spiny or crested. Differs from Dracontioides in leaf blade never fenestrate, spathe lanceolate, very long-acuminate and usually spirally twisted towards apex , ovary locules with (1-)2 to several ovules.