Philydrum Gaertn.

Scientific Description

Family Philydraceae.

Habit and leaf form. Herbs. Plants leaves succulent. Perennial. Leaves basal and cauline. Plants with a basal concentration of leaves; rhizomatous (with fibrous roots). Mesophytic, or xerophytic. Leaves alternate; spiral and distichous (the lower distichous, the upper spiral); sessile; sheathing. Leaf sheaths with joined margins (basally), or with free margins. Leaves more or less edgewise to the stem; simple. Leaf blades entire; flat; linear; many-nerved; parallel-veined; without cross-venules. Leaves eligulate; without stipules. Leaf blade margins entire. Leaf anatomy. Hairs present (sparsely woolly), or absent. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’ (10–25-flowered); in spikes. Inflorescences scapiflorous (scapes 1 to several, simple or sparsely branched); terminal. Flowers bracteate (the bracts rather large, sheathing the flowers); small to medium-sized; fragrant, or odourless; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers cyclic; tetracyclic. Perigone tube absent. Perianth of ‘tepals’; 6 (but disguisedly so), or 4 (by misinterpretation); 2 -whorled; theoretically isomerous; joined (the two lateral (upper) members of the inner whorl fused with the upper (median) of the outer whorl to form a large, broad, entire or 3-toothed upper lip, the median (lower) member of the inner whorl forming a large lower lip, and the laterals of the outer whorl small), or free (by misinterpretation); petaloid; hairy; yellow. Androecium 1. Androecial members adnate (to the lateral tepals). Androecium exclusively of fertile stamens. Stamens 1; reduced in number relative to the adjacent perianth. Anthers with cochleate locules; non-versatile; dehiscing via longitudinal slits; extrorse to introrse (becoming helically coiled at anthesis); tetrasporangiate. Pollen shed in aggregates; in tetrads. Gynoecium 3 carpelled. The pistil 1 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; superior. Ovary unilocular; 1 locular (imperfectly trilocular, with deeply intrusive placentation). Gynoecium stylate. Styles 1 (straight); attenuate from the ovary, or from a depression at the top of the ovary; apical; shorter than the ovary at anthesis to about as long as the ovary at anthesis. Stigmas 1; 3 - lobed; dry type; papillate; Group II type. Placentation parietal. Ovules in the single cavity 15–100 (‘many’); non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; hairy; dehiscent; a capsule (oblong-ellipsoidal). Capsules loculicidal. Seeds ovoid, with corona; copiously endospermic; with starch. Embryo well differentiated. Cotyledons 1. Embryo straight. Testa spirally striate-tuberculate. Seedling. Hypocotyl internode absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated; assimilatory; dorsiventrally flattened. Coleoptile absent. Seedling cataphylls absent. First leaf dorsiventral. Primary root ephemeral.

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