Steudnera K.Koch

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

Distribution

S. China, Assam to Indo-China.

Diagnostic

Medium to robust herbs with aerial, erect to creeping stems; leaf blade peltate, ovate to ovate-oblong, fine venation colocasioid; spathe fully expanded in flower; spadix fertile to apex, male and female zones contiguous; flowers unisexual, perigone absent; ovary 1-locular, ovules many, placentae parietal. Differs from Remusatia in female flowers with staminodes, spathe not constricted and stems trunk-like or creeping.

General Description

HABIT : medium sized to robust herbs, usually evergreen, sometimes seasonally dormant, stem epigeal, stout, erect or creeping, covered with fibrous remains of leaves and cataphylls. LEAVES : few to several. PETIOLE : sheath very short. BLADE : peltate, ovate or ovate-oblong, acuminate, often emarginate at base; basal ribs short, well-developed, primary lateral veins pinnate, forming submarginal collective vein very near margin, marginal vein also present, secondary and tertiary laterals arising from the primaries at a wide angle, then arching towards leaf margin and forming ± conspicuous interprimary collecting vein, higher order venation reticulate. INFLORESCENCE : solitary. PEDUNCLE : shorter than petiole. SPATHE : yellow or ± dark purple within, ovate or ovate-lanceolate, acuminate, not constricted, barely convolute at base, ± fully expanded at anthesis, lower part probably persistent to fruiting stage, upper part becoming reflexed and revolute, probably eventually marcescent. SPADIX : much shorter than spathe, densely flowered, female zone cylindric, often longer than male, mostly adnate to spathe, male zone contiguous with female, cylindric, ellipsoid or subglobose, fertile to apex, obtuse. FLOWERS : unisexual, perigone absent. MALE FLOWER : 3-6-androus, stamens connate, synandrium strongly lobed, apically truncate, common connective relatively small, impressed at apex, thecae oblong, contiguous, dehiscing by apical pore. POLLEN : inaperturate, ellipsoid-oblong, small (mean 22 µm.), exine striate. FEMALE FLOWER : gynoecium surrounded by whorl of 2-5, short, claviform staminodes, more rarely staminodes absent, ovary subglobose to ovoid, 1-locular, ovules numerous, hemiorthotropous, funicle distinct, placentae 2-5, parietal, in basal part only or extending from base to apex, style ± lacking, stigma strongly 2-5-lobed. BERRY : ovoid, many-seeded. SEED : ovoid to ellipsoid, testa costate, embryo axile, endosperm copious.

Habitat

Tropical humid forest; geophytes on forest floor.