Apatophyllum McGill.

Scientific Description

Family Celastraceae.

Habit and leaf form. Shrubs (subshrubs); laticiferous, or non-laticiferous and without coloured juice. Plants unarmed (although leaves pungent). Leaves cauline. Young stems cylindrical, or tetragonal. To 0.02–1 m high. Xerophytic. Leaves small; alternate; spiral; decurrent on the stems, or not decurrent on the stems; ‘herbaceous’, or leathery, or membranous; sessile; non-sheathing; simple. Leaf blades dorsiventral; entire; solid; grooved adaxially; linear (to acicular); parallel-veined. Mature leaf blades adaxially glabrous; abaxially glabrous. Leaves with stipules. Stipules persistent. Leaf blade margins entire. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent; glandular hairs absent. Unicellular hairs absent. Complex hairs absent. Branched hairs absent. Extra-floral nectaries absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the disk. Entomophilous.

Inflorescence and flower features. Flowers solitary; axillary. Inflorescences single axillary flowers. Flowers pedicellate; ebracteate; bracteolate (at base of pedicels); usually small; regular; 5 merous; cyclic; nearly always tetracyclic. Hypogynous disk present; intrastaminal; annular. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous (basally connate); blunt-lobed; imbricate; exceeded by the corolla; regular; green, or yellow; non-fleshy; persistent. Calyx lobes ovate to triangular (to broadly deltoid). Corolla present; 5; 1 -whorled; polypetalous; imbricate; regular; glabrous abaxially; glabrous adaxially; green, or white, or cream; persistent. Petals oblong to ovate, or triangular (to narrowly deltoid). Fertile stamens present. Androecial members definite in number. Androecium 5. Androecial members free of the perianth; all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; all more or less similar in shape; isomerous with the perianth; oppositisepalous. Filaments glabrous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse; bilocular; bisporangiate, or tetrasporangiate. Pollen shed in aggregates, or shed as single grains; when in aggregates in tetrads, or in polyads. Fertile gynoecium present. Gynoecium 2–3 carpelled (the third when present sometimes abortive). The pistil 2–3 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious; superior (although with disk adnate to the lower part). Ovary plurilocular; 2–3 locular; sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1; obscurely 2–3 - lobed. Placentation basal, or axile. Ovules 2 per locule; pendulous, or ascending; apotropous; with ventral raphe, or with dorsal raphe (when pendulous); anatropous.

Fruit and seed features. Fruit non-fleshy; yellow (straw-coloured); not hairy; dehiscent; a capsule. Capsules loculicidal. Fruit 2–3 celled; 2–3 locular; 1–2 seeded (rarely). Seeds 1 per locule. Seeds endospermic. Endosperm oily. Seeds small; arillate; wingless. Embryo well differentiated. Cotyledons 2 (large, flat, foliaceous). Embryo straight. Testa smooth; brown.

Geography, cytology, number of species. World distribution: Australia. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, Queensland, and New South Wales. Eremaean Botanical Province. The genus has three very restricted species that are widely disjunt from each other, considered to be a relictual pattern by Cranfield & Lander (1992). A genus of 3 species; 1 species in Western Australia; 1 endemic to Western Australia.