Cosmelia R.Br.

Scientific Description

Family Epacridaceae.

Habit and leaf form. Shrubs; evergreen; leptocaul, or pachycaul. Helophytic to xerophytic. Leaves small to medium-sized; alternate; spiral, or four-ranked; ‘herbaceous’, or leathery; imbricate; petiolate to sessile; sheathing; pungent-pointed; simple. Leaf blades entire; flat; palmately veined, or parallel-veined (ostensibly so, the parallel veins in the lamina originating palmately from a single leaf trace); cross-venulate, or without cross-venules. Leaves without stipules. Leaf blade margins flat. Leaf anatomy. Hairs absent. Stem anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous. Pollination mechanism unspecialized.

Inflorescence and flower features. Flowers solitary; erect or sometimes drooping, terminating axillary branchlets or peduncles covered with leaflike bracts, which pass gradually into the sepals and form an involucre round them; bracteate; bracteolate; medium-sized (20–30 mm); fragrant, or odourless; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; annular (short). Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; polysepalous; imbricate; more or less equalling the corolla (or scarcely exceeded by the corolla); regular; herbaceous or more or less coloured; persistent. Corolla 5; 1 -whorled; gamopetalous; lobed (lobes spreading towards the end). Corolla lobes markedly shorter than the tube. Corolla imbricate; tubular (cylindrical); regular; glabrous abaxially; glabrous adaxially; red; persistent, or deciduous. Androecium 5. Androecial members adnate (to the corolla); all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5. Staminal insertion in the throat of the corolla tube. Stamens remaining included; isomerous with the perianth; oppositisepalous; all alternating with the corolla members. Filaments flattened. Anthers basifixed, or adnate; becoming inverted during development, their morphological bases ostensibly apical in the mature stamens; non-versatile; dehiscing via longitudinal slits (by a single median slit); finally introrse (inverting during development); bisporangiate; unappendaged. Pollen shed in aggregates, or shed as single grains; without viscin strands; in diads, or in triplets, or in tetrads. Gynoecium 5 carpelled. The pistil 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 5 locular. Gynoecium stylate. Styles 1; from a depression at the top of the ovary; apical. Stigmas 1; truncate, or clavate, or capitate. Placentation axile. Ovules 3–20 per locule (i.e. ‘numerous’); pendulous; non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Seeds endospermic. Endosperm oily. Seeds wingless. Embryo well differentiated. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia. South-West Botanical Province. N = 13.

Additional characters Prophylls numerous.