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Bombax L.
Sp.Pl. 2:511 (1753)

Name Status: Current

Scientific Description
S. Hamilton-Brown, Friday 3 October 2008

Common name. Kapok Trees. Family Bombacaceae.

Tribe Adansonieae.

Habit and leaf form. Trees (often with buttress roots); deciduous. Plants spiny, or unarmed. The spines axial (and trunk). To 10–45 m high. Leaves medium-sized; alternate; spiral; petiolate; compound; palmate. Leaflets 3–9. Leaf blades dorsiventral. Mature leaf blades adaxially glabrous, or pubescent, or scaly; abaxially glabrous, or pubescent, or scaly. Leaves with stipules. Stipules caducous. Leaf blade margins entire. Leaf anatomy. Hairs present; complex hairs present. Complex hairs stellate.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; in panicles. The terminal inflorescence unit cymose. Flowers pedicellate; bracteolate (3 bracteoles). Bracteoles deciduous. Flowers large; more or less regular. Floral receptacle developing an androphore. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; lobulate (3–5-lobed or truncate); erect; exceeded by the corolla; campanulate, or urceolate; not persistent. Epicalyx absent. Corolla present; 5; 1 -whorled; polypetalous (adnate to the base to the staminal tube); imbricate; hairy abaxially (stellate-woolly); hairy adaxially; plain; red. Petals oblong, or obovate. Androecium present. Fertile stamens present. Androecial members indefinite in number. Androecium 50–100 (i.e. ‘many’). Androecial members coherent (filaments shortly connate into a tube at the base, the outermost stamens further connate into bundles, the innermost stamens free or connate in pairs above the connate base); 5 - adelphous (in 5 bundles). The androecial groups opposite the sepals. Androecium exclusively of fertile stamens. Stamens 50–100 (i.e. ‘many’). Anthers recurved; dehiscing via longitudinal slits (i.e. a peripheral slit); unilocular. Pollen grains psilate. Gynoecium 5 carpelled. The pistil 5 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 5 locular; sessile. Gynoecium stylate. Styles 1. Stigmas 1; 4–5 - lobed. Placentation axile. Ovules 50–100 per locule (i.e. ‘many’).

Fruit and seed features. Fruit 60–120 mm long; not hairy. Pericarp woody with solid septa. Fruit dehiscent; a capsule (ellipsoid). Capsules loculicidal (by 5 valves). Dispersal unit the seed. Fruit 5–100 seeded (i.e. ‘many’). Seeds small; arillate; conspicuously hairy (floccose).

Geography, cytology, number of species. World distribution: mainly Africa and Asia. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province. 2n = 72 for B. ceiba, B. buonopozense and B. costatum. A genus of 8 species; 1 species in Western Australia; 0 endemic to Western Australia.

Etymology. From Greek and Latin for "silkworm, silk"; refers to the silky wool surrounding the seeds, which was used for stuffing pillows.

Keys to Bombax L.