Livistona R.Br.

Scientific Description

Family Arecaceae.

Habit and leaf form. Slender to robust shrubs, or ‘arborescent’ (treepalms, trunk smooth, sometimes annulate or with persistent leaf bases); evergreen. Plants spiny, or unarmed. Pachycaul. Mesophytic, or xerophytic. Leaves very large; alternate; spiral; leathery; petiolate (with or without marginal thorns); sheathing. Leaf sheaths tubular; with joined margins. Leaves compound; epulvinate; palmate (costapalmate, induplicate, segment apices entire or divided for part of their length). Leaf blades without cross-venules. Leaves ligulate, or eligulate; without a persistent basal meristem (presumably). Vernation conduplicate. Leaves becoming compound by ontogenetically predetermined splitting. Vegetative anatomy. Plants with silica bodies (spheroidal). Leaf anatomy. Leaf blade epidermis without differentiation into ‘long’ and ‘short’ cells. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male, or functionally female. Unisexual flowers present, or absent. Plants hermaphrodite, or dioecious (rarely). Floral nectaries present, or absent. Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in panicles. The terminal inflorescence unit cymose. Inflorescences axillary; flowers spirally arranged on erect, pendulous or divaricate rachillae; spatheate. Flowers small; more or less regular; 3 merous; cyclic. Perigone tube absent. Perianth with distinct calyx and corolla, or of ‘tepals’; 6; 2 -whorled (3+3); isomerous; sepaloid, or petaloid; different in the two whorls; white, or cream, or yellow. Calyx if outer whorl so interpreted, 3; gamosepalous. Corolla if inner whorl so interpreted, 3; gamopetalous (basally). Fertile stamens present, or absent (female flowers, rare). Androecium 6. Androecial members adnate (to the perianth); coherent; 1 - adelphous (filaments united to form a fleshy ring, tipped with short, slender, distinct filaments); 2 -whorled. Androecium exclusively of fertile stamens. Stamens 6; diplostemonous. Anthers medifixed; dehiscing via longitudinal slits; latrorse; tetrasporangiate. Fertile gynoecium present, or absent (male flowers, rare). Gynoecium 3 carpelled (usually only one carpel developing). Carpels isomerous with the perianth. Gynoecium syncarpous; synstylous. Stigmas dry type; papillate; Group II type. Ovules non-arillate; anatropous.

Fruit and seed features. Fruit fleshy, or non-fleshy; not an aggregate (usually), or an aggregate (when more than one carpel develops). The fruiting carpel indehiscent; drupaceous. Fruit 1 seeded. Seeds ellipsoidal or globose; endospermic. Endosperm ruminate, or not ruminate; oily, or not oily. Seeds without starch. Cotyledons 1. Embryo achlorophyllous. Seedling. Germination consistently cryptocotylar (regardless of cotyledon form). Hypocotyl internode absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated, or compact; non-assimilatory. Coleoptile present, or absent. Seedling cataphylls absent. First leaf dorsiventral. Primary root persistent, or 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, Queensland, and New South Wales. Northern Botanical Province.

Additional characters Pollen grains mono- sulcate.