Taxonomic implications of macro and micromorphological characters in the genus Brachythecium (Brachytheciaceae, Bryopsida) from the Western Himalayas: A combined light and scanning electron microscopic analysis.

Brachythecium Schimp. is one of the most complex and diverse genus among the pleurocarpous mosses, having almost 150 species distributed around the world. The current study presents a detailed morphological analysis of the six species of the genus Brachythecium in Western Himalayas, Pakistan. The study reports the first detailed micromorphological investigation of the leaf surfaces (gametophyte) of the studied species because in pleurocarpous mosses, mostly sporophyte micromorphology has been studied. The objective of the study was to present a comparative light (LM) and scanning electron microscopic (SEM) analysis to describe the detailed morphology of bryophytes in Pakistan. A systematic method was used in the field as well as in their microscopic studies. Based on these findings, morphological and micromorphological features based on LM and SEM observations, qualitative and quantitative characters, taxonomic keys, distribution and habitat are discussed. The size of the leaf, leaf cells, seta, and other parts were noted, but slight variation was observed when we compare these measurements with the same species collected from different geographical regions. The leaf micromorphology reveals some interesting features like the nature of cell walls, cell shapes, and the surface of the lumen. Because the specimens used for SEM were air-dried, the cells were mostly constricted and compressed. In almost all species except in Brachythecium garovaglioides, the papillae or cell wall ornamentations were absent. The study will help to contribute to the taxonomy of this genus or its family, especially in relation to the Western Himalayas.

Morphological characterization of Hypnaceae (Bryopsida, Hypnales): Investigating four genera from Western Himalayas by using LM and SEM techniques.

The Hypnaceae is one of the largest and diversified family among the pleurocarpous mosses which consists of nearly 60 genera and 1,000 species around the world. In Pakistan, it is represented by 15 species and 8 genera. The current research article provides the detail morphological investigation of four different species (genera) of the family Hypnaceae that is, Gollania clarescens, Hypnum revolutum, Homomallium andoi, and Taxiphyllum taxirameum in the Western Himalayas, Pakistan. The research article reports the first SEM study of the leaf surfaces of the studied taxa, along with comprehensive morphological characters of the four species. The main objective of the research project is to present the comparative light and scanning electron microscopic study to discuss the morphology in detail because previously the family is just reported in different bryophyte checklists of the Western Himalayas. Based on results, morphological characters, micromorphological observations, qualitative and quantitative attributes, taxonomic keys for the studied taxa, distribution, and habitat are described. Stereoscope was used to analyze different qualitative characters, and light microscope was used to observe and measure the laminal and alar cells of the leaf. The SEM study reveals many important surface features like cell shape and cell wall. The laminal cells were mostly linear and elongated with thin cell walls. The specimens used for the SEM were air dried, so the laminal cells were somewhat constricted and concaved. The current study project will help to make the contribution in the taxonomy and morphology of this family.