Morphological variations in geographically isolated populations of Bryum coronatum Schwager (Bryaceae, Bryales)

Abstract

Four populations of Bryum coronatum Schwager (Bryaceae, Bryales), collected from widely separated geographic regions - Sambalpur, Odisha; Lataguri, West Bengal; Gangtok and Changu, Sikkim; were studied with regard to variation in taxonomically significant morphological features as well as their dimension of both gametophytic and sporophytic features. In this study special emphasis has been put on spore dimension and spore ornamentation pattern as revealed by Scanning Electron Microscopy (SEM). Dimension of taxonomically significant morphological parameters were measured for four populations and were subjected to analysis of variance (One way ANOVA) and Principal component analysis (PCA). ANNOVA results showed significant variation for all features except leaf length and upper leaf cell breadth. PCA results corroborated ANNOVA result only for upper leaf cell breadth. Spore ornamentation as revealed through SEM, is found to be bacculate in all the populations. CCA graph revealed that summer, winter temperature and monsoon rainfall influence leaf size, lamina cell size, capsule size, peristome size and spore size. With the help of above mentioned observations and statistical analysis the morphological variations, due to phenotypic plasticity have been quantified to reach at a meaningful conclusion. Taxonomic significance of spore dimension and wall ornamentation is also discussed.