Dicranales

Abstract: The systematic position of the rare moss Pulchrinodus inflatus (Hook. f. & Wils.) Allen, which is only known in sterile condition, has so far been dubious. The species has been transferred between very distant families of the Bryopsida, such as the haplolepideous Dicnemonaceae (Dicranales) or the diplolepideous Pterobryaceae (Leucodontales). To clarify the systematic relationships of Pulchrinodus at the molecular level, three DNA regions, the cpDNA trnL–F and psbT–H regions and the nrDNA ITS2, were sequenced. The psbT–H region is employed for the first time in the Bryopsida. In maximum parsimony and maximum likelihood trees, Pulchrinodus is clearly separated from the genera Dicnemon, Eucamptodon and Mesotus of Dicnemonaceae. Furthermore, a close relationship to genera of the Pterobryaceae (Hildebrandtiella, Pterobryon) is also not indicated. The molecular data, therefore, contradict a position of Pulchrinodus either in the haplolepideous mosses or in the Hypnales (today including the Leucodontales). Instead, the placement of Pulchrinodus in the molecular trees, near to species of the Rhizogoniaceae and Orthotrichaceae, together with its unique combination of gametophytic characters, indicates that Pulchrinodus occupies an isolated position in a grade diverging early within the diplolepideous mosses.

Abstract: Bryophyta comprises one of the earliest lineages of land plants that had implemented remarkable innovations to their lipid metabolic systems for successful adaptation to terrestrial habitat. This study presents a comprehensive investigation of fatty acid profiles of mosses from Eastern Himalayas with an aim to trace their chemotaxonomic and evolutionary implications. Fatty acid compositions of 40 random mosses belonging to major families of Bryophyta were explored by gas chromatographic analysis. A diverse array of saturated, monounsaturated and polyunsaturated fatty acids including rare acetylenic fatty acids were detected. Hexadecanoic acid (C16:0), 9,12 (Z,Z)-octadecadienoic acid (C18:2n6) and 9,12,15 (Z,Z,Z)-octadecatrienoic acid (C18:3n3) were the predominant fatty acids in all the mosses. However, quantitative variation of C20 polyunsaturated fatty acids (PUFAs), specifically 5,8,11,14 (Z,Z,Z,Z)-eicosatetraenoic acid (C20:4n6), among the investigated mosses was the most prominent outcome. The diplolepidous members of Bryidae, especially the mosses of Hypnales, Bryales and Bartramiales contained higher amount of C20 PUFAs compared with the haplolepidous orders. Principal component analyses based on individual fatty acids and other related parameters validated C20:4n6 content and the ratio of C20:4n6/C18:2n6 as the apparent chemotaxonomic discriminants. The prevalent notion of considering 9,12,15-octadecatrien-6-ynoic acid (C18:4a) as the chemomarker of Dicranaceae has also been challenged, since the compound was detected not only in different families of Dicranales, but also in a Pottiales member, Leptodontium viticulosoides. Therefore, an ensemble of fatty acids instead of a single one can be considered as the chemical signature for taxonomic interpretation which may also be vital from an evolutionary standpoint.

Abstract: Mosses with haplolepideous peristomes form a major lineage within the arthrodontous taxa, the Dicranidae. Relationships among lineages within the Dicranidae are explored using three cpDNA regions: rbcL, rps4, and the region spanning trnL(UAA)- trnF(GAA). Maximum parsimony analyses of combined data sets support robust clades that correspond to traditionally recognized families. Phylogenetic relationships of 71 exemplar taxa rooted with five outgroup taxa identify 13 major clades within the Dicranidae. Predominantly the monophyly of these groups is strongly supported, although relationships among the clades are ambiguous. The phylogenetic implications of the current taxon sampling include 1) the Dicranidae are monophyletic, 2) the Pottiales are polyphyletic with the Calymperaceae and Octoblepharaceae cladistically distant from the Pottiaceae, and these two former families should be transferred to the Dicranales, 3) the Dicranales are polyphyletic, with Ditrichaceae and Rhabdoweisiaceae more closely...