Abstract
In the course of a worldwide revision of the genus Syntrichia, we identified problems in the circumscription of some species of the genus as well as among some allied genera grouped in the tribe Syntricheae. This is the case for the two propagulose Syntrichia amphidiacea and S. gemmascens, closely related to Streptopogon. We analyzed phylogenetic relationships between these species, based on nuclear (ITS) and two plastid (trnL-F and trnG) markers and morphological features. Species delimitation using molecular data was consistent with our preliminary morphological inference. Phylogenetic analyses were performed using maximum likelihood and Bayesian inference methods. Our results placed Syntrichia amphidiacea in the Streptopogon clade. Syntrichia gemmascens is also included in Streptopogon in spite of the discrepancy of the ITS and plastid relationships, which could be evidence of an exchange of genetic material between species in various lineages in the Pottioideae. Streptopogon is maintained as a separate genus on the basis of morphology characters, and we consider the differentiation of laminal papillae and the presence of a stem central strand as new characters in the genus. We accept Sagenotortula as distinct genus sister to Syntrichia. We consider the lack of costal dorsal epidermis and the differentiation of a crescent-shaped costal dorsal stereid band as distinctive generic characters in Syntrichia. Additionally, we include Syntrichia percarnosa as a new synonym for S. breviseta. Three names are lectotypified.
Highlights
The Pottiaceae, characteristic of harsh habitats [1], are one of the most complex and diverse family of mosses and are widely distributed around the world [2–5]
The analysis indicates maximum support (PP = 1; BS = 100) for a monophyletic group composed of specimens strongly grouped of Syntrichia gemmascens (PP = 1; BS = 100), S. amphidiacea (PP = 0.95; BS = 100) as sister to Streptopogon calymperes but without support, and Streptopogon erythrodontus (PP = 1; BS = 100), with S. fragilis as sister (PP = 1; BS = 83)
The analysis indicates strong support (PP = 0.98; BS = 91) for a monophyletic group composed of strongly grouped specimens of Syntrichia gemmascens (PP = 1; BS = 100), S. amphidiacea (PP = 1; BS = 100) as sister to Streptopogon calymperes but without support, and the strongly supported clade of S. cavifolius and S. erythrodontus (PP = 0.96; BS = 82), with Syntrichia fragilis as sister (PP = 0.98; BS = 88)
Summary
The Pottiaceae, characteristic of harsh habitats [1], are one of the most complex and diverse family of mosses and are widely distributed around the world [2–5]. The taxonomy of Pottiaceae has been complicated and its generic circumscriptions are the subject of ongoing debate [6]. Is one of the most diverse genera within the family, with about 90 species currently known with a focus of diversification in South America [7,8]. Zander [3,9] and Ochyra [10] established its morphological characterization and distinguished it from Tortula Hedw., focusing the weight of its generic differentiation on the anatomy of the costa. A few years later, Spagnuolo et al [11] supported this segregation with molecular data. Only a few phylogenetic studies on Syntrichia have been conducted to date, all with a limited number of species [12–15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
