The genus Alocasia (Araceae) in Australasia

The genus Alocasia (Araceae) is revised for Australasia. Thirteen species are recognised and keyed; eleven are endemic to and one is thought to be introduced to and escaped in Papuasia; A. brisbanensis (F.M. Bailey) Domin is endemic to Australia, and is redescribed; five are new to science. The genus Xenophya Scott is reduced to synonymy with Alocasia and the new combinations A. brancifolia (Scott) A. Hay and A. lauterbachiana (Engler) A. Hay are made. Infrageneric groups (incl. Xenophya) are informally erected. Variation in shoot architecture is discussed. Line drawings are provided of previously unillustrated or obscurely illustrated species. Distributions are partly mapped. It is noted that the aroid crop plants A. macrorrhizos (L.) G. Don and Cyrtosperma merkusii (Hassk.) Schott, on the one hand, and Amorphophallus paeoniifolius (Dennst.) Nicolson and Colocasia esculenta (L.) Schott, on the other, have markedly different patterns of distribution in Australasia, suggesting two waves of eastward dispersal. Species of Alocasia recently cited as hostplants in the protologues of several spadicicolous species of Diptera Drosophilidae and Neurochaetidae are redetermined.