HABIT : seasonally dormant herbs, tuber depressed globose. LEAF : solitary. PETIOLE : terete, sheath short. BLADE : pinnatifid, pinnatisect or bipinnatifid, pinnae (9-)11-14, elliptic, entire or pinnatifid (with all intermediates), acute, upper lobes decurrent, lower ones sessile to shortly stalked; primary lateral veins of ultimate lobes pinnate, running into margin, higher order venation reticulate. INFLORESCENCE : 1(-2) per floral sympodium, appearing before leaf. PEDUNCLE : much shorter than petiole. SPATHE : erect or slightly fornicate, boat-shaped, very shortly convolute at base, not constricted, purple, persistent at least in lower part. SPADIX : fertile to apex, female zone contiguous with and much shorter than male zone. FLOWERS : unisexual, perigone absent. MALE FLOWER : 3-7-androus, stamens free or connate to different degrees into a synandrium, connective slender, sometimes stipe-like between thecae (G. mirabile), otherwise inconspicuous, thecae globular, sometimes remote from one another, dehiscing by apical pore or slit, pistillode present or absent, if present composed of 3-4 stylodia with slightly lobed or discoid-capitate apices (stigmatoids). POLLEN : inaperturate, ellipsoid, medium-sized (mean 34 µm, range 27-42 µm.), exine verrucose (G. mirabile) to retiverruculate, sometimes verrucae irregularly formed and flattened (G. vargasii). FEMALE FLOWERS : gynoecium surrouonded by whorl of 6-8 filiform or subclavate staminodes, ovary subglobular to broadly ovoid, (2-)4-5(-7)-locular, ovules 1 per locule, orthotropous, ovoid, funicle half as long as ovule, placenta axile at base of septum, style short to long, stigma 4-5-lobed or subcapitate. BERRY : globular to depressed-globular, blackish-purple to purple, sometimes upper surface somewhat warty (G. vargasii), stigma and style remnants persistent. SEED : ovoid, globular to ellipsoid, testa brownish, smooth to rough, embryo elongate, endosperm copious.
Seasonally dormant tuberous geophytes; leaf blade with reticulate fine venation; flowers unisexual, perigone absent; female flowers surrounded by a whorl of free staminodes; ovules orthotropous. Differs from Synandrospadix in staminodes in female flowers filiform to subclavate, male flowers with stamens free or connate to different degrees into a synandrium (always entirely connate in Synandrospadix) and leaf blades pinnatifid, pinnatisect or bipinnatifid.