The Sorapillaceae has been placed by some authors either near the Fissidentaceae or in the Eubryales suborder Rhizogoniineae because of its peculiar leaf structure closely resembling that of the Fissidentaceae and what was appar- ently a single peristome. Examination of the peristomes of Sorapilla sprucei Mitt. and S. papuana Broth. & Geh. revealed that the peristome is double and reduced. On the basis of the reduced double peristome, pseudoparaphyllia, complanate leaves, immersed lateral sporophytes, pleurocarpous habit, elongated basal cells in the leaves, and a sparsely hairy calyptra, a placement of the Sorapillaceae in the Isobrvales near the Neckerineae, as advocated by Fleischer, is correct. The genus Sorapilla was established by Spruce and Mitten (in Mitten 1869) to accom- modate a single species, S. sprucei, from Ecuador. In 1900 Brotherus and Geheeb (in Brotherus 1900) described an additional species, S. papuana from New Guinea. The genus was placed by Mitten (1869) in the Skitophylleae (which included Fissidens, Eustichia and Bryoxiphium) primarily on the basis of its distichous and equitant leaves. Fleischer (1907) considered Fissidens and Sorapilla to have little natural relationship to one another. In his view, the leaves of Sorapilla and Phyllogonium were closer to each other than either was to the leaf of Fissidens. Thus, he placed Sorapilla in its own family, the Sorapillaceae, in the Isobryales near the Phyllogoniaceae. According to Fleischer, Sorapilla exhibited a close relationship with the Neckeraceae by its similar habit, its peristome-which he considered to be rudimentary and diplolepideous-and its hairy ca- lyptra. Brotherus (1909), like Mitten, placed Sorapilla in the Fissidentaceae on the basis of leaf structure and the apparent single row of peristome teeth, which have, unlike the exostome of a typical diplolepideous moss a single row of scales dorsally. In 1924, however, Brotherus recognized the family Sorapillaceae, and placed it in the Eubryales, suborder Rhizogoniineae, with which it shares a two-rowed complanate leaf arrangement and erect, regular radially symmetrical sporophytes. Dixon (1932) also maintained the Sorapillaceae in the Eubryales, suborder Rhizogoniineae, which he felt represented a heterogeneous group of variably developed mosses, often with a single peristome ... Sorapilla is a pleurocarpous moss. This is evidenced by the immersed and laterally borne sporophytes and by foliose pseudoparaphyllia (Fig. 1). The latter character is one found only in certain pleurocarpous mosses (Ireland 1971). The distichous and equitant leaves of the Sorapillaceae, which also possess vaginant laminae and both dorsal and ventral laminae, very nearly approach the leaf structure of the Fissidentaceae, as was observed by Salmon (1899). The leaf cells are elongated at the base (Fig. 2), isodiametric above, and enlarged and hyaline along the edge of the vaginant laminae forming a border