The systematic significance of testa anatomy in the Leguminosae — an illustrated survey

Seed from all three subfamilies of the Leguminosae was surveyed for anatomical features of the testa which could be used in the systematics of the family. An atlas of testa anatomy is presented, and the possible adaptive significance of certain seed structures is discussed. Seed of the Mimosoideae and Caesalpinioideae remain incompletely separated, but the shape of the micropyle constitutes a useful accessory character. In addition certain genera in these subfamilies have features which are anomalous in the family. Features of the micropyle, cuticle and light line typically characterize the papilionoid seed, but the only characters invariably restricted to this subfamily are hilar features traditionally recognized as such. However, testa anatomy is very useful within the Papilionoideae and certain tribes or groups of phylogenetically related tribes can be recognized by various features of the testa, particularly cuticle sculpturing and micropyle shape. Similarities between mimosoid and caesalpinioid seeds are plesiomorphous, and cannot necessarily imply greater phylogenetic relationship. The occurrence of a direct relationship between epidermal and hypodermal thickness in papilionoid seed suggests an early stabilization of this adaptive structure