Streblotrichum
Dioicous. Asexual reproduction by spheric brown rhizoidal tubers. Turves on soil. Stem erect, simple or irregularly branched, densely covered by rhizoids; central strand present or absent; hyalodermis absent; sclerodermis present. Leaves ligulate, lanceolate, ovate or spathulate (not in Victoria), erect- to wide-spreading when moist, crisped when dry; apex rounded to acute, often apiculate; costa subpercurrent, percurrent or excurrent, with a differentiated adaxial epidermis, with quadrate and densely papillose adaxial superficial cells, with a weak adaxial stereid band, without a hydroid strand, with an abaxial stereid band, with elongate abaxial superficial cells, with a weakly differentiated abaxial epidermis; margin entire, plane, undulate (not in Victoria) or recurved near base, without a border; laminal cells in apical half quadrate, pluripapillose, with a yellow KOH reaction; basal laminal cells differentiated equidistant from base from margin to costa, quadrate to rectangular, smooth, chlorophyllose or hyaline. Acrocarpous. Perichaetial leaves strongly differentiated and convolute. Seta yellow, becoming brown when old. Capsule erect, straight, cylindric, exserted, operculate, with a revoluble annulus. Calyptra cucullate, smooth, glabrous. Operculum conic. Peristome of 32 filaments, twisted anticlockwise.
Three species in northern temperate regions, with one also occurring in Australia and New Zealand, but limits of the genus poorly understood and may possibly include additional species (see below).
Streblotrichum was segregated from Barbula by Kučera et al. (2013), and is based on Barbula sect. Convolutae. Kučera et al. (2013) included three species in Streblotrichum, that formed a group well separated from the type of Barbula in phylogenies based on combined nuclear and chloroplast DNA sequence data. However, additional species not sampled in their study, such as Victorian B. calycina Schwägr. and B. subcalycina Müll.Hal., may also be better placed in Steblotrichum than Barbula where they are currently placed. Kučera et al. (2013) discussed the need to conduct further molecular phylogenetics using a broader sample of species that have been included in Barbula, particularly in the Southern Hemisphere, to better understand genus limits of Barbula and its segregate genera.
Kučera, J.; Košnar, J.; Werner, O. (2013). Partial generic revision of Barbula (Musci: Pottiaceae): Re-establishment of Hydrogonium and Streblotrichum, and the new genus Gymnobarbula. Taxon 62: 21–39.