The Leguminosae

Abstract

Botanists appear to agree that the great expansion of the angiosperms in the Cretaceous began in the tropical rain forest (some say on the borders of that zone — Takhtajan, 1969), and that the Leguminosae was one of the early families at that time. Corner (1949) expounded upon his theory that the fruit of the durian (Durio zibethinus, Bombacaceae) was the primitive fruit of modern flowering plants, by showing how this arillate fruit has changed into the dry follicle or capsule with small, often winged, easily detached, ex-arillate seeds, or into the berry, drupe or nut. Corner found in the Leguminosae eighteen genera with the aril more or less covering the seed, in the sub-families Mimosoideae, Caesalpinioideae, Swartzioideae and Papilionaceae. This is regarded as a relic distribution; nearly every arillate genus shows in different species all stages in reduction or loss of the aril.