Phyllanthus L.

Scientific Description

Family Euphorbiaceae.

Habit and leaf form. Trees, or shrubs, or lianas, or herbs; non-laticiferous and without coloured juice. Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves minute to medium-sized; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy; petiolate to sessile; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; pinnately veined. Leaves with stipules. Stipules scaly, or leafy, or spiny, or represented by glands; 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, or dioecious. Female flowers solitary, or aggregated in ‘inflorescences’ (then clustered in the same or different axils as the male flowers). Male flowers aggregated in ‘inflorescences’ (clustered, smaller than female flowers); without pistillodes. Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; often in fascicles (usually 1–3 male flowers and 1 female flower per fascicle), or in racemes, or in panicles. Inflorescences axillary. Flowers bracteate, or ebracteate; minute to small; regular. Floral receptacle developing an androphore, or with neither androphore nor gynophore (? depending on interpretation). Free hypanthium absent. Hypogynous disk present; of separate members (glands), or annular. Perianth sepaline; (5–)6; 1 -whorled, or 2 -whorled. Calyx often petal-like, (5–)6; 1 -whorled; gamosepalous (basally); imbricate; regular; persistent. Fertile stamens present, or absent (female flowers). Androecium (2–)3(–6). Androecial members free of the perianth; free of one another, or coherent (filaments wholly or partially connate). Androecium exclusively of fertile stamens. Stamens (2–)3(–6); reduced in number relative to the adjacent perianth to isomerous with the perianth; erect in bud, or inflexed in bud. Anthers dehiscing via longitudinal slits, or dehiscing transversely; 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 (depending on interpretation of partially connate styles); superior. Ovary plurilocular; 3 locular. Styles 3; free, or partially joined (shortly connate); usually 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; hemianatropous.

Fruit and seed features. Fruit non-fleshy, or fleshy; a schizocarp (capsular). Mericarps 3(–4) (or more, rarely). Fruit elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds 2 or more per mericarp (2-seeded). Seeds trigonous; endospermic. Endosperm oily. Seeds non-arillate (dry). Cotyledons 2 (much wider than the radicle). Embryo straight, or curved. 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, South Australia, Northern Territory, Queensland, and New South Wales. Northern Botanical Province, Eremaean Botanical Province, and South-West Botanical Province.

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