Swetha Balakrishnan, Rani G
Abstract: The fossa ornamentation of the mature oospore wall of three species of the genus Chara, viz., C. zeylanica Willd., C. braunii Gmelin. and C. corallina Klein ex. Willd. and two species of the genus Nitella viz., Nitella furcata Agardh. and N. pseudoflabellata Braun., of South India have been observed. There are no published reports on SEM studies on both Chara and Nitella species from South India. Various patterns ranging from spongy to rough surface, granular to pusticular, and reticulate ornamentation are observed for the various specimens. Oospore features are presented in detail which includes the length and width ratio of the oospores, the fossa width, the number of striae, and, clawed base, etc. There are very few old reports on the presence and absence of clawed base oospore, which is discussed in the present work. The fossa ornamentations of above specimens are compared with the earlier reports of Chara zeylanica Klein. Ex. Willd. var. sejuncta f. sejuncta, C. braunii f. schweinitzii (A. Br.) R. D. W., Nitella furcata subsp. Megacarpa f. tumulosa and N. pseudoflabellata subsp. pseudoflabellata var. imperialils f. wattii. The present SEM work thus helps to identify the above species at the infraspecific level.
Keywords: Chara, Nitella, SEM, Fossa ornamentation