Flueggea Willd.

Scientific Description

Family Euphorbiaceae.

Habit and leaf form. Trees, or shrubs; deciduous (mostly), or evergreen; non-laticiferous and without coloured juice. Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves minute to large; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy; shortly petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; pinnately veined. Leaves with stipules. Stipules scaly, or leafy; caducous, or persistent. Leaf blade margins entire. 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, or dioecious. Male flowers with pistillodes (usually 2–3-branched), or without pistillodes (rarely). Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; in fascicles. Inflorescences axillary. Flowers pedicellate; bracteate (bracts inconspicuous); minute to small; regular; 4–7 merous. Free hypanthium absent. Hypogynous disk present; of separate members, or annular (in male flowers of 4–7 members, these sometimes connivent or fused; in female flowers patelliform, sometimes thickened, entire, variously lobed or angled). Perianth sepaline; 4–7; 1 -whorled. Calyx 4–7; 1 -whorled; gamosepalous (basally); imbricate; regular; non-accrescent. Fertile stamens present, or absent (female flowers). Androecium 4–7. Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens 4–7; isomerous with the perianth; erect in bud, or inflexed in bud. Anthers dehiscing via longitudinal slits; extrorse; bisporangiate, or tetrasporangiate. Pollen grains subglobose, 3-colporate, semitectate. Fertile gynoecium present, or absent (male flowers). Gynoecium (2–)3(–4) carpelled. The pistil (2–)3(–4) celled. Gynoecium syncarpous; synovarious, or synstylovarious (depending on interpretation of partially connate styles); superior. Ovary plurilocular; (2–)3(–4) locular. Styles 3; free, or partially joined (basally connate); forked (the branches sometimes dilated); 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; hemianatropous.

Fruit and seed features. Fruit columella persistent; non-fleshy (usually), or fleshy; a schizocarp (capsular), or indehiscent (and baccate, succulent to crustaceous). Mericarps 3. Fruit a capsule, or a drupe; elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds 2 per locule; normally 2 or more per mericarp (2-seeded). Seeds endospermic (endosperm copious). Endosperm oily. Seeds non-arillate. Cotyledons 2 (wider and much longer than the radicle). Embryo achlorophyllous; straight to curved. Testa thin, crustaceous, smooth to reticulate or verruculose. 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, Queensland, and New South Wales. Northern Botanical Province and Eremaean Botanical Province.

Additional comments. Western Australian species of Flueggea can be separated from Phyllanthus by the presence of a well-developed pistillode in the staminate flower.