Systematics of Pilidiostigma (Myrtaceae)

A systematic treatment is presented for the six species of Pilidiostigma (Myrtaceae), one newly described. Pilidiostigma is distinguished from other fleshy-fruited genera of Myrtaceae by the combination of its elliptic anthers, capitate to peltate stigma, testa usually chartaceous-membranous and covered with numerous large yellow or white oil glands (except for P. tetramerum), 1-3 locular ovary, and globular embryo in which the cotyledons and hypocotyl often are not, or only slightly, differentiated. The genus occurs predominantly in eastern Australia in wet forests east of the Great Dividing Range from near sea level to 1300 meters, although P. papuanum also extends into New Guinea. The new species Pilidiostigma sessile is described from northeastern Queensland and is diagnosed by its sessile or nearly sessile, basally rounded to cordate leaves. Lectotypes are designated for P. rhytispermum and P. glabrum. Detailed descriptions are provided for each species, along with a key, and profiles of essential oils are reviewed for most species.