Desmidium

Abstract: In a survey employing epifluorescence microscopy with the DNA fluorochrome DAPI, associations between bacteria and filamentous desmids were found to be commonplace in acidic, Sphagnum-dominated Wisconsin peat-lands. Bacteria were associated with all genera of filamentous desmids encountered including Desmidium, Hyalotheca, Onychonema, Spondylosium, and Teilingia. Although only associations involving filamentous desmids having mucilaginous sheaths are illustrated here, bacteria were also noted on taxa lacking sheaths as well as some unicellular forms. Bacteria on Desmidium majus Lagerheim, D. grevillii (Kutz.) De Bary, and Hyalotheca dissiliens (Smith) Breb. ex Ralfs tended to be concentrated in small pockets in the sheath material located near the isthmus and in the region between adjacent cells in the filament, whereas those associated with Spondylosium pulchrum (Bail.) Archer were more evenly distributed throughout the sheath. Most bacteria were rodshaped. Those associated with S. pulchrum, D. grevillii, and D. majus ranged from 1.1 to 11.2 μm in length. Bacteria within the sheaths of H. dissiliens and D. grevillii were Gram-negative. A second morphologically distinct population of bacteria was found at the sheath margin in D. majus and D. grevillii. Field collections containing filamentous desmids were examined with scanning electron microscopy and bacteria associated with Desmidium majus were investigated with transmission electron microscopy.

Abstract: Present communication deals morpho-taxonomic description of 11 fresh water algae belonging to class Chlorophyceae and Bacillariophyceae. Chlorophycean genera are Pediastrum Meyen (1 sp), Cladophora (2 spp), Staurastrum (3 spp), Onychonema (2 spp) and Desmidium (1 sp) while Bacillariophycean genera are Navicula (1 sp) and Rhopalodia (1 sp). Key words: Bacillariophyceae, Chlorophyceae, Eastern Uttar Pradesh, Fresh water algae doi:10.3126/on.v3i1.338 Our Nature (2005) 3: 77-80

Abstract: The present paper treats 33 taxa of desmids belonging to 8 genera collected from ponds, paddy fields, ditches and streams of Quilon district, Kerala. Of these, Cosmarium clepsydra NORDST. var. duplex PRESCOTT, Cosmarium depressum (NAG.) LUND f., Cosmarium reniforme (RALFS) ARCHER var. compressum NORDST. f., Cosmarium subdanicum WEST et WEST, Cosmarium umbilicatum LUTKEM., Staurastrum striolatum (NAG.) ARCHER var. divergens WEST et WEST and Desmidium grevillei (KUTZ.) DE BARY f. are supposed to be new to India and all the taxa are reported for the first time from Kerala. In der Arbeit werden 33 Taxa aus 8 Genera der Desmiaceae behandelt, die in Teichen, Reisfeldern, Graben und Flussen im Quillon Gebiet, Kerala, gesammelt wurden. Aus diesen Funden sind neu fur Indien und werden erstmals aus Kerala erwahnt: Cosmarium clepsydra NORDST. var. duplex PRESCOTT, Cosmarium depressum (NAG.) LUND f., Cosmarium reniforme (RALFS) ARCHER var. compressum NORDST. f., Cosmarium subdanicum WEST et WEST, Cosmarium umbilicatum LUTKEM., Staurastrum striolatum (NAG.) ARCHER var. divergens WEST et WEST und Desmidium grevellei (KUTZ.) DE BARY f.

Abstract: Thirty eight desmidian taxa belonging to family Desmidiaceae of class Chlorophyceae are reported and discussed. Genera are Euastnim Ehrenberg (3 sp. and 1 var.), Cosmarium Corda ex Ralfs (14 sp.,7 var. and 2 forms), Onychonema Wallich (1 var.), Desmidium Agardh (1sp.), Spondylosium Breb.(lform), Micrasterias Agardh (4sp.) Staurastrum Mayen (1 var., 1 form) and Arthrodesmus Ehrenberg (1sp.and 1 form). Morpho-taxonomy and descriptions of taxa are based on cell walls structure, shape and size of semi cells/ isthmus. Two species of genus Euastrum and one species of Cosmarium have been described under open nomenclature. These desmidian algae are being reported from Bahraich,Shrawasti and Gonda districts of North-Eastern Uttar Pradesh and they constitute new records for the area.