Amorphophallus Decne.

Scientific Description

Family Araceae.

Habit and leaf form. Herbs; laticiferous. Leaves well developed (not present at flowering). Perennial. Leaves basal. Cormous. Helophytic, or mesophytic. Not heterophyllous. Leaves medium-sized to very large; petiolate (appearing conventionally ‘petiolate’ when the sheath shed); with ‘normal’ orientation; compound; pinnate. Leaf blades pinnately veined; cross-venulate, or without cross-venules. Leaves ligulate, or eligulate. Axillary scales present, or absent. Leaves without a persistent basal meristem. Vegetative anatomy. Plants without silica bodies. Leaf anatomy. Guard-cells not ‘grass type’. Stem anatomy. Secondary thickening absent. Roots. Roots with velamen, or without velamen.

Reproductive type, pollination. Fertile flowers functionally male and functionally female. Unisexual flowers present. Plants monoecious. The unisexual flowers aggregated in different parts of the same inflorescence. Anemophilous, or entomophilous. Pollination mechanism conspicuously specialized, or unspecialized.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in spikes. The terminal inflorescence unit seemingly racemose. Inflorescences scapiflorous, or not scapiflorous; consisting of specialised spikes (‘spadices’); spadix stout, terete, densely flowered, the female flowers grouped below a contiguous portion of male flowers, without sterile flowers, terminated by a large sterile appendix; pseudanthial; spatheate (spathe erect, not constricted; basal portion short, convolute; blade often broad, the margins often undulate). Flowers ebracteate; ebracteolate; small (numerous); (these or the spadix) fragrant, or malodorous; cyclic. Perianth absent. Fertile stamens present, or absent (when female). Androecium 2–4. Androecial members free of one another; 1 -whorled, or 2 -whorled. Androecium exclusively of fertile stamens. Stamens 2–4; with sessile anthers. Anthers dehiscing via pores; extrorse; bisporangiate, or tetrasporangiate. Pollen shed as single grains. Fertile gynoecium present, or absent (when male). Gynoecium 1–4 carpelled. The pistil 1–4 celled. Gynoecium syncarpous, or monomerous; of one carpel, or synstylovarious to eu-syncarpous; superior. Carpel apically stigmatic. Ovary unilocular, or plurilocular; 1–4 locular. The ‘odd’ carpel when trilocular, posterior. Gynoecium shortly stylate, or non-stylate. Styles apical. Stigmas wet type, or dry type; non-papillate; Group II type. Placentation when syncarpous/unilocular, parietal, or basal, or apical; when plurilocular, axile. Ovules in the single cavity when unilocular, 1; when plurilocular, 1 per locule; pendulous, or horizontal, or ascending; orthotropous, or hemianatropous, or anatropous.

Fruit and seed features. Fruit fleshy; indehiscent; a berry. Seeds non-endospermic. Perisperm absent. Seeds with starch. Cotyledons 1. Embryo straight (linear). Seedling. Hypocotyl internode present, or absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll compact; assimilatory, or non-assimilatory. Coleoptile absent. Seedling non-macropodous. First leaf dorsiventral. Primary root ephemeral.

Physiology, biochemistry. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province.

Additional characters Leaves solitary. Leaves erect.