| 1 | Stem of inflorescence leafless. Young inflorescences with a closed cover of spirally arranged, polygonate, peltate scales, which are caducous in anthesis. Styles 2. |
| 1' | Stem of inflorescence with leaves, the upper ones covering the young inflorescence; the latter without such scales. Style 1. |
| 2 | Stem of inflorescence more or less scaly, originating endogenously from a more or less spherical tuber forming a sheath round the base of the stem; perianth of male flowers tubular, lobes 4 or incon spicuous |
| 2' | Stem of inflorescence without scales, apparently originating exogenously from an elongated tuber, no sheath observed; perianth of male flowers conspicuously 4-lobed |
| 3 | Leaves (in Mal.) up to 30, wide, rounded, or blunt. Flowers arranged on a globular to elongate axis. Tubers with surface fine granular to coarsely warted, scattered stellate warts mostly present. Female flowers free from each other, intermixed with club-shaped spadicles. Tuber with wax. |
| 3' | Leaves very many (80-100), linear, very acute. Flowers arranged on the flattish, thickened apex of the stem. Tubers with surface densely pubescent, never granular or warted. Female flowers apparently adnate to each other, spadicles absent. Tuber starchy |
