Gyrocarpus
Content
Description
Deciduous trees.
Leaves simple, entire or 3(-5)-lobed; veining palmate.
Inflorescence axillary or terminal, a more or less repeatedly dichotomous corymbose thyrse, ebracteate, sometimes precocious.
Flowers bisexual or unisexual (mostly male), numerous, small (less than 1.5 mm). Bisexual and female flowers with (6-)7(-8) perianth segments (tepals), four of these forming an opposite pair, each pair consisting of two adjacent tepals with common basal meristem growing out during and after anthesis into two spathulate wings on top of the nut; style sigmoid, stigma capitate; stamens 4 or 5, or less, filaments provided with small dorsal glands or not; clavate staminodes alternating with stamens.
Fruit a samara; nut ovoid or elongate-ellipsoid with two large apical spathulate wings; pericarp hard, rather thick.
Seeds with spongy testa (in one American species membranous); cotyledons contortuplicate.
Distribution
E Africa present, Pantropical present, Southern America, tropics present
A pantropical genus of 3 species: G. jatrophifolius Chiov. in Central America; G. hababensis Domin in E Africa; G. americanus widely distributed throughout the tropics
Dispersal
The falling fruit quickly rotates, the wings being stretched out in an angle of 120-140°, facilitating a steady fall created by the air-resistance, and achieving dispersal over short distances (Von Wahl 1897, Biblioth. Bot. 40: 14). The fruits of G. americanus and G. hababensis can be carried by water, the buoyancy due to the spongy seed-coat. Testified by the wide coastal distribution of these species, this kind of dispersal apparently is effective.