Taxonomic significance of fruit and seed structure in the subfamily Cassinoideae (Celastraceae)

Abstract

The paper reports on the macro- and micromorphology and anatomy of fruits and seeds in 19 species representing 13 African and American genera of subfamily Cassinoideae (family Celastraceae). A diversity of carpological characters was identified: fruit type and peculiarities of its dehiscence; presence of trichomes on fruit surface; subtypes of pyrenaria (polymerous, olygomerous, dimerous, pseudomonomerous); number of seeds, morphology of the seed (shape, presence/absent of outgrowths); the ratio of parenchymatous (ground) and sclerenchymatous (supporting) cell elements in the pericarp, cell shape and number of cell layers in the seedcoat. Fruit and seed characters support the differences between genera, also reflect on their possible relationship. The traits revealed are also used to substantiate and support the recent taxonomic revision of many genera, primarily African. The array of revealed fruit and seed traits strongly support previous taxonomic decisions to define most genera of the subfamily Cassinoideae in a narrow sense. It is especially relevant in the taxonomy of the African representatives, characterizing among others the distinct indigenous flora of the Cape Floristic Region.