Taxonomic revision of Astraea (Euphorbiaceae)

Astraea is a genus of tribe Crotoneae (Euphorbiaceae: Crotonoideae) widely distributed in the Neotropical region. Its highest diversity is found in eastern Brazil, and a few weedy species were most likely introduced and naturalized in the Paleotropics. Species of Astraea may be recognized by the usually deeply lobed leaves, lacking basilaminar or acropetiolar nectaries; spiciform inflorescence with bisexual cymules at the base and staminate cymules toward the apex; pistillate flowers with a segmented nectary and multifid styles; staminate flowers with an imbricate calyx, petals bearing dense moniliform trichomes at the basal portion of their margin and 11–15 stamens; and usually tetragonal and verrucose seeds, bearing a caruncle. Based on recent advances in the taxonomic and systematic knowledge of Astraea, we present a taxonomic revision of the genus. Thirteen species are recognized based on morphological characters. We present a full review of morphology and geographical distribution of the genus, along with data on ecology, phytochemistry and medicinal uses, gathered from the literature and fieldwork. Along with an identification key to the species, we provide descriptions, illustrations and photographs, as well as etymology and vernacular names, geographical distribution and ecology, conservation status and comments on taxonomic and nomenclatural matters. Fifteen lectotypes and three neotypes are newly designated here.