Morphological characterization of Hypnaceae (Bryopsida, Hypnales): Investigating four genera from Western Himalayas by using LM and SEM techniques. Issue 6 (16th February 2020) - Khan, Aamir Shehzad
Abstract: 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. Abstract : Light and Scanning electron microscope (SEM) are comparatively used to investigate the four species of the family Hypnaceae belonging to four different genera. Light microscope (LM) is used to study the morphological characters of the species and LM micrographs of different parts of leaves are described. SEM is used to study the micromorphological features of the gametophyte (mainly leaf surface) and SEM micrographs of leaf surfaces are discussed. Qualitative and quantitative characters of both gametophyte and sporophyte are studied. Worldwide distribution and habitat are described. Based on their specific characters, taxonomic keys for the identification of the studied species are given.