Bombax.
Seen in Queensland in Family Bombacaceae or Subfamily Bombacoideae in Family Malvaceae.
Six species are from northern Australia and S.E. Asia with 2 from West Africa.
Some are commonly cultivated in tropical and subtropical areas.
They are known as the Red Cotton, Silk Cotton or Kapok tree.
The deciduous trees can be up to 60 m high.
Spines on young trunks may persist on older ones.
Old trunks, up to 4 m across often have winged buttresses.
The spirally arranged leaves are on a petiole with stipules having a pointed tip.
Leaves, up to 50 cm across are palmate with 5, 7 or 9 leaflets.
Usually directly attached to the end of the petiole they may on be a short petiolule.
The centre leaflet is usually the largest.
Axillary or terminal inflorescences are a solitary flower or a small cluster.
They usually appear on bare branches.
On a pedicel under 1 cm long the flowers are up to 8 or 10 cm long.
The rim of the tough tubular or cup-shaped calyx can be flat or have (3-4) 5 small to large lobes.
There may be glands on the outer surface.
The 5 ovate, oblong or obovate petals may have hairs on the outer surface.
Their base is fused to the bottom of the stamen tube and the tip is often asymmetric.
Most species have red flowers but some are white or yellow.
Sepals and petals fall before the fruit develop.
The bases of the few to hundreds of stamens are fused into a short tube.
On the rim the free filaments are in 1 or 2 whorls with most in the outer.
In each whorl the filaments are in groups.
The dorsifixed anthers open outwards through longitudinal slits.
The ovary, of 5 fused carpels has 5 locules each with numerous ovules.
The slender style, with 1 or 5 stigma lobes extends past the stamens.
Fruit are a woody loculicidal capsule with short silky hairs on the outer surface.
The central axis in the capsule, the columella remains when the seeds have gone.
The numerous roughly pear-shaped seeds are surrounded by a thick layer of fibres.
The white, pale brown or reddish woolly fibres are made of cellulose.
It is commonly known as kapok due to its similarity to the kapok of Ceiba pentandra fruit.
J.F.
