Dysoxylum Blume
Bijdr.Fl.Ned.Ind. 7:172 (1827)

Name Status: Current
Browse to the list of specimens for Dysoxylum Blume

Scientific Description
B. Richardson, Thursday 8 September 2016

Family Meliaceae.

Family Meliaceae, Subfamily Melioideae, Tribe Guareeae.

Habit and leaf form. Trees. ‘Normal’ plants. Leaves cauline. To 7–30 m high. Mesophytic. Leaves medium-sized, or large, or very large; alternate; spiral; petiolate; not gland-dotted; with ‘normal’ orientation; compound; pinnate (rarely with limited apical growth); paripinnate, or imparipinnate. Leaflets 6–22; 3–21.5 cm long. Lateral leaflets alternate, or opposite. Leaflets elliptic, or oblong, or ovate; cuneate at the base, or oblique at the base, or rounded at the base (‘obtuse’); flat. Leaflet margins flat. Leaf blades dorsiventral; pinnately veined. Mature leaf blades adaxially glabrous, or pubescent; abaxially glabrous, or pubescent. Leaf blade margins entire; flat. Leaf anatomy. Hairs present. Unicellular hairs present.

Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male, or functionally female. Unisexual flowers present. Plants hermaphrodite, or dioecious. Plants not viviparous; homostylous. Floral nectaries present. Nectar secretion from the disk.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence many-flowered. Flowers in racemes, or in spikes, or in panicles. Inflorescences simple, or compound. The terminal inflorescence unit racemose. Inflorescences axillary. Flowers pedicellate; small; regular; 3–6 merous; cyclic. Perianth with distinct calyx and corolla; 6–12; 2 -whorled; isomerous, or anisomerous (rarely). Calyx present; 3–5(–6); 1 -whorled; gamosepalous, or polysepalous (rarely); lobed, or entire (rarely). Calyx lobes markedly shorter than the tube, or about the same length as the tube, or markedly longer than the tube. Calyx glabrous, or hairy; imbricate, or open in bud; exceeded by the corolla; unequal but not bilabiate. Corolla present; 3–6; 1 -whorled; polypetalous (sometimes fused to the lower or upper half of the staminal tube); imbricate, or valvate; regular; glabrous abaxially, or hairy abaxially; glabrous adaxially, or hairy adaxially; white, or cream, or pink. Corolla members entire. Androecial members definite in number. Androecium 8–10. Androecial members free of the perianth, or adnate (partially, to the corolla in the lower or upper half of the staminal tube); all equal; coherent (filaments fused into a tube); 1 - adelphous; 1 -whorled. Stamens 8–10; all more or less similar in shape; diplostemonous (or nearly so). Anthers all alike. Gynoecium 2–5 carpelled. The pistil 2–5 celled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2–5 locular. Gynoecium stylate. Styles 1; apical. Stigmas 1; 1 - lobed; discoid or less frequently small and capitate. Placentation axile. Ovules 1–2 per locule.

Fruit and seed features. Fruit 8–32 mm long; dehiscent; a capsule. Capsules loculicidal. Dispersal unit the seed. Cotyledons 2. Seedling. Germination cryptocotylar (Pennington & Styles (1975)).

Geography, cytology, number of species. World distribution: found in Indomalesia, Australia, New Guinea, Polynesia and New Zealand. Native of Australia, or adventive. Endemic to Australia, or not endemic to Australia. Australian states and territories: Western Australia, or Northern Territory, or Queensland, or New South Wales. Northern Botanical Province. N=10,20,42; 2n=80,84. A genus of 60 species; 1 species in Western Australia; D. latifolium.

Taxonomic Literature

  • Wheeler, J. R.; Rye, B. L.; Koch, B. L.; Wilson, A. J. G.; Western Australian Herbarium (1992). Flora of the Kimberley region. Western Australian Herbarium. Como, W.A.