11. Bombacaceae
木棉科 mu mian ke
Authors: Ya Tang, Michael G. Gilbert & Laurence J. Dorr
Trees, usually large, often deciduous; trunks sometimes spiny, often buttressed; bark fibrous, with mucilaginous exudates; indumentum usually stellate or tufted. Leaves alternate, spiral; stipules inconspicuous, caducous; petiole pulvinate; leaf blade often palmately compound (simple and lobed in Ochroma), margin often entire. Inflorescences axillary, 1(or 2)-flowered, rarely many-flowered. Flowers bisexual, actinomorphic, large and showy. Epicalyx of 3 bracts, inconspicuous and caducous. Calyx shortly cylindrical, truncate, or irregularly 3-5-lobed, sometimes splitting. Petals 5, joined at base with androecium and falling as one unit, imbricate. Stamens usually very many (3-15 in Ceiba); filaments usually united in lower half into a filament tube around style, tube sometimes lobed, with stamens in 5 groups with completely united filaments and sessile anthers; anthers usually 1-celled, apparently 2-celled and non-septate in Ceiba, sometimes many anthers united into an apparent many-celled "super-anther"; pollen usually spheroidal, ± smooth, reticulate; staminodes absent. Ovary superior, syncarpous, carpels usually 5; ovules 2 to many per locule, axile, anatropous; style 5-lobed. Fruit a 5-valved capsule, or hard and indehiscent (e.g., Adansonia), many-seeded with seeds often embedded in endocarp hairs (kapok), less often fruit winged or juicy and few-seeded. Seeds sometimes winged.
About 30 genera and ca. 250 species: found widely in tropics, especially tropical America; three genera (two introduced) and five species (two introduced) in China.
See the comments under the Malvaceae (p. 264) for the relationships of the Bombacaceae.
Durio Adanson was at one time associated with this family but has always been regarded as anomalous and molecular data show it to be most closely related to the Helicteroideae (Sterculiaceae) but so distinct morphologically that it might better be placed in its own family or subfamily. Fruits of Durio zibethinus Murray (榴莲 liu lian, durian) are often available in S China, but attempts to cultivate it in China have not been successful and all fruits are imported from SE Asia.
Adansonia digitata Linnaeus (African baobab tree, 猴面包树 hou mian bao shu) and Ochroma pyramidale (Cavanilles ex Lamarck) Urban (O. lagopus Swartz, 轻木 qing mu, noteworthy as the source of the extremely lightweight timber, balsa) are only found in botanical gardens and do not merit full treatments.
Li Hen. 1984. Bombacaceae. In: Feng Kuo-mei, ed., Fl. Reipubl. Popularis Sin. 49(2): 102-112.
