AbstractThe taxonomically strongly isolated monotypic genusJubulopsis Schust. [type:J. novaezelandiae(Hodgs.&S. Am.) Schust.] forms a unique element in the Jungermanniales. It has been assigned toJubula Dumortand toNeohattoriaKamimura, and has been stated to be allied toFrullaniaDumort. - all genera of Jubulaceae (Porellineae). Discovery of the sporophytes conclusively shows the genus belongs to the Lepidolaenineae Schust. The coelocaule ofJubulopsis; the lack of a perianth and calyptra; the 4-lobed underleaves; the peculiar beaked capsule with a 3–4-layered wall; the free elaters; the massive haustorium—all preclude placing the genus in Jubulaceae. Although the numerous, minute, homogeneous oil-bodies and the coelocaule suggest a position in the Lepidolaenaceae,Jubulopsisis shown to differ from Lepidolaenaceae in lacking watersacs of all stem underleaves; in the non-incised water-sacs; the massive haustorium; the I-spiral elaters; and theFrullania-like thickenings of epidermal sporangium cells. The form of the lobule (‘water-sac’), however, is shown to be similar to that developed in most Jubulaceae and the stylus can be readily matched to that in some taxa ofFrullania. The genus is placed in a new family Jubulopsidaceae, endemic to New Zealand, whose synthetic features suggest a position near the base of the Lepidolaenineae. This suborder, and Porellineae, are assumed to share a common ancestor with the plesiomorphic features such as are retained in extant Ptilidiineae. The gametophytic features ofJubulopsissuggest that a multiordinal classification of the Jungermanniales is untenable.