Leptopus Decne.

Scientific Description

Family Euphorbiaceae.

Habit and leaf form. Shrubs, or herbs; non-laticiferous and without coloured juice. Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves small to medium-sized; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy; petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; pinnately veined, or palmately veined. Leaves with stipules. Stipules scaly, or leafy; caducous, or persistent. Leaves without a persistent basal meristem. Leaf anatomy. Urticating hairs present, or absent. Stem anatomy. Nodes tri-lacunar, or unilacunar. Secondary thickening developing from a conventional cambial ring, or anomalous; from a single cambial ring.

Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Unisexual flowers present. Plants monoecious. Male flowers with pistillodes (rudimentary ovary small). Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in clusters; L. decaisnei with usually several male flowers and 1 female flower per cluster. Inflorescences axillary. Flowers bracteate, or ebracteate; minute to small; regular. Floral receptacle developing an androphore, or developing a gynophore. Free hypanthium absent. Hypogynous disk present; disc glands opposite petals. Perianth with distinct calyx and corolla, or sepaline (sometimes, in female flowers); 10–12, or 5–6 (when corolla absent); 1 -whorled, or 2 -whorled; when two-whorled, isomerous. Calyx 5, or 6; 1 -whorled; gamosepalous (connate towards the base); regular; persistent; accrescent. Corolla present, or vestigial to absent (in female flowers); when present, 5, or 6; polypetalous; regular. Fertile stamens present, or absent (female flowers). Androecium 5, or 6. Androecial members free of the perianth; free of one another, or coherent (connate below). Androecium exclusively of fertile stamens. Stamens 5, or 6; isomerous with the perianth; oppositisepalous; erect in bud, or inflexed in bud. Anthers dehiscing via longitudinal slits; extrorse, or introrse; bisporangiate, or tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium syncarpous; synovarious, or synstylovarious; superior. Ovary plurilocular; 3 locular. Styles 3; free, or partially joined; deeply forked; apical. Stigmas 6; dry type; papillate, or non-papillate; Group II type. Placentation axile, or apical. Ovules 2 per locule; pendulous; epitropous; with ventral raphe, or with dorsal raphe; collateral; non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; a schizocarp. Mericarps 3. Fruit elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds curved, trigonous; endospermic. Endosperm oily. Seeds non-arillate. Cotyledons 2 (usually wider than the radicle). Embryo straight, or curved. Testa rugose. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Mustard-oils present, or absent.

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 and Eremaean Botanical Province.