New taxa of Plagiothecium (Plagiotheciaceae) from Pakistan.

A revision of specimens of Plagiothecium deposited in the herbarium of Pakistan Museum of Natural History (PMNH) collected during a Japanese lead project on Cryptogams in the Western Himalaya (Pakistan) shows that the material consists of five taxa. Of the studied samples, the most common taxa were from the P.denticulatum complex, including Plagiotheciumdenticulatumvar.obtusifolium, new to Pakistan. Examination of the rest of the collection showed that it consists of specimens with a unique combination of qualitative and quantitative characteristics of their gametophyte. For example, for small plants, with small asymmetrical, folded leaves, gradually tapering into long, acuminate, not denticulate apex, whose leaf cells are long and narrow, making the cell areolation tight, the name Plagiotheciumfilifolium is proposed. For other plants with large leaves, loosely arranged on the stem, concave, symmetrical to slightly asymmetrical, with denticulate apex and long decurrency composed of rectangular and spherical, inflated cells, the name Plagiotheciumhiguchii is proposed. However, within this material, specimens differ in terms of the length and width of the leaf cells and therefore, within this taxon, two varieties are distinguished: Plagiotheciumhiguchiivar.higuchii and Plagiotheciumhiguchiivar.brevicellum.

Palyno-anatomical characters and their systematic significance in the family Apiaceae from Chitral, eastern Hindu Kush, Pakistan.

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 µm and equatorial diameter of 21.6 µm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 µm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 µm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 µm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 µm and abaxial 50.25 × 39.40 µm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.

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.

Implication of scanning electron microscopy in the seed morphology with special reference to three subfamilies of Fabaceae.

The current research work was aimed to determine the morphological variation in the seeds of subfamilies Caesalpinioideae, Mimosoideae, and Papilionoideae using scanning electron microscope to investigate the different seed features including; Seed length, width, weight, hilum shape, position, fracture line pattern, pleurogram shape, texture crudeness, ornamentation wall, and surface ornamentation. A total of 12 species were collected. The study reveals that the seed types alters from psilate to rugose, pleurogram shape from lunar to U shape, hilum shape from elliptical to depressed, hilum position from terminal to subterminal, fracture line pattern from reticulate irregular ridges to psilate with regular ridges, texture crudeness from fine to coarse, surface ornamentation from reticulate to psilate, and ornamentation wall also varies from thin to thick. In all the studied species, it was found that seed surface was brown in color except in Senna alata, in which seed surface was black. Regarding the seed size, it was found that the smallest seed was observed for Sesbania sesban, while the largest seed was observed for Pongamia pinnata. The present research article indicates the taxonomic significance of seed morphology in the subfamilies Caesalpinioideae, Mimosaceae, and Papilionoideae.

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.