Description from Flora of China
Ictodes Bigelow; Spathyema Rafinesque.
Herbs, large, glabrous, seasonally dormant. Rhizome erect, stout, with thick roots. Leaves few to several, petiolate; petiole long, with sheath; leaf blade subcordate to cordate-ovate, large, apex acute to cuspidate; midvein strong, primary lateral veins pinnate and arching toward apex, running into inconspicuous marginal vein, secondary lateral veins and higher order venation reticulate to transversely reticulate. Inflorescences 1 or 2 in a sympodium, appearing before or with leaves; peduncle long but only shortly exserted above ground; cataphylls surrounding peduncle. Spathe convolute at base, somewhat to widely gaping at apex, thick, boat-shaped or conchiform, apex 2-keeled, rostrate, curving forward. Spadix stipitate, globose to broadly ellipsoid, much shorter than spathe and hidden within. Flowers bisexual, with perigone; tepals 4, arching and imbricate. Stamens 4, free; filaments flattened; connective slender; thecae oblong, dehiscing by longitudinal slit; pollen grains ellipsoid, monosulcate, exine reticulate, apertural exine verrucate. Ovary of gynoecium (pistil) somewhat immersed in spadix axis, 1-loculed; ovule 1, orthotropous; funicle very short; placentation apical-parietal; stylar region long attenuate; stigma punctate-disciform. Infructescence globose to broadly ellipsoid, berries densely arranged. Berry with tepals and style persistent to ripe fruiting stage, base of berry immersed in spongy spadix axis. Seed globose; testa thin, smooth; embryo globose, large; endosperm very sparse, only a single cell layer thick. 2n = 30, 60.
The other species in the genus are Symplocarpus foetidus (Linnaeus) Salisbury ex W. P. C. Barton (the type species) in North America; S. egorovii N. S. Pavlova & V. A. Nechaev in Russia (Far East), and S. nabekuraensis Otsuka & K. Inoue in Japan, but the latter is very close to S. renifolius and is better considered as an infraspecific taxon of it.
Four or five species: E Asia, North America; two species in China.
(Authors: Li Heng (李恒 Li Hen); Peter C. Boyce, Josef Bogner)