Families of Flowering Plants of Australia

Araceae

Araceae is a large, pantropical family. In Australia, most species occur beneath wet (or occasionally dry) rain forests, or sometimes (Gymnostachys) in open eucalypt forests. A few temperate species are naturalised in wet places in southern Australia. The unusual genus Pistia is a floating aquatic from still waterbodies in northern Australia; it is a declared noxious weed in New South Wales.

Characteristic features of the family Araceae in Australia include:

usually herbs (occasionally climbers with adventitious roots or aquatic plants), often with large, somewhat thick, fleshy leaves arising from an underground corm or thickened rootstock; plants always glabrous.
flowers reduced, massed in a thick spike (called a spadix) enveloped (at least when young) in a single, often thick-textured bract (the spathe); often the spike has female flowers at the base and male flowers at the apex

Description

Evergreen woody or herbaceous vines climbing by root suckers, or epiphytes, or perennial terrestrial herbs; rarely aquatic herbs free-floating or rooted in the substrate with their leaves floating or emergent. Perennating by corms, tubers or rhizomes. Vegetative reproduction by corms, tubers, rhizomes, stolons, detached stem parts or bulbils. Extra-floral nectaries absent or on the foliage. Stem internodes terete, oval, slightly to strongly flattened or distinctly angular. Internal secretions not obvious or of milky sap (latex). Plants glabrous or with simple, non-glandular, uniseriate hairs. Leaves alternate and spiral or distichous, cauline or all or mostly basal if herbs, petiolate, subsessile, or sessile, or peltate; pulvinae present or absent. Stipule-like lobes present or apparently absent. Lamina simple, once compound, bicompound or tricompound, ternate, palmate or imparipinnate, symmetric or conspicuously asymmetric, pinnatifid or pinnatisect, filiform, acicular, subulate, linear, lanceolate, ovate, elliptic, oblanceolate, ovate, oblong, flabellate or orbicular; base cuneate, attenuate, rounded, cordate, hastate or sagittate, lobed or auriculate or oblique; margins entire, ±flat, revolute or recurved; venation pinnate, or palmate, or parallel, with the midrib conspicuous or inconspicuous, and the tertiary venation reticulate or not; surfaces not punctate; herbaceous, leathery or succulent; distinctive odour absent or aromatic. Leaf ligule present or absent. Domatia absent, or rarely consisting of pits in the vein angles. Male and female flowers occurring on the same plant, or with all the flowers bisexual. Inflorescences terminal or axillary, consisting of spadices, with the male flowers above the female flowers, or solitary flowers. Spathes absent or present, white or purple inside. Bracts present or absent. Pollination by insects. Flowers odourless, fragrant or malodorous; sessile. Floral disc absent; nectaries present on the carpels. Perianth regular, of 1 whorl only or 2 ±similar whorls, with 4 or 6 (–8), free, sepaloid or petaloid segments, or vestigial or absent, valvate in bud, white, cream, yellow, magenta, purple, violet, green, grey, brown or black, without contrasting markings; inner whorls herbaceous or leathery. Fertile stamens (1–) 4–6 (–12), usually opposite to and free of the perianth segments, free of the ovary and style, distinct from each other or fused by their anthers, all ±equal or in pairs. Staminal filaments present or absent. Anthers basifixed, not versatile, opening outwards or terminally by pores, by short slits or by longitudinal slits; 2 or 4-celled. Ovary superior and sessile. Carpels 1 or 3, fused; ovary with 1 or 3 locules. Style terminal, single and unbranched or single and branched above. Ovules 1–numerous per locule, stalked or sessile; placentation basal, parietal or axile. Fruit a fleshy, indehiscent berry or rarely a drupe; the perianth on the maturing fruit dry and persistent or growing larger. Disseminule micro-surface ±smooth, reticulate or finely striate, white, cream, yellow, orange, red, blue or green, glossy or dull. Seeds 1–numerous per fruit. Aril present or absent. Cotyledons 1. Embryo straight or curved.

(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Araceae has not yet been published in the Flora of Australia. It will appear in Volume 39.

Australian genera of Araceae (as recognised for the Flora of Australia)

* = all species introduced

Alocasia
Amorphophallus
*Arisarum
*Arum
*Colocasia
Gymnostachys
*Pistia
Pothos
Remusatia
Rhaphidophora
Scindapsus
Typhonium
*Zantedeschia