Morphology and Taxonomy of Oscillatoria princeps Vaucher Ex Gomont (Oscillatoriales, Oscillatoriaceae)

Background: Oscillatoria princeps has been reported from various parts of India for its diversity but not studied in detail about morphology and reproduction hence we try to fill that lacuna.

Methods: Samples were collected from a stream near Kanyakumari district, Tamil Nadu. One part was preserved in 4% formalin, while the other part was brought to unialgal culture by streaking method. The cultures were grown and maintained in ASN III (-NaCl) medium at the photoperiodic culture racks with 8 hours light and 16 hours dark. Semi-permanent slides were prepared and Leica EC3 Microsystems was used for observation and documentation.

Findings: The alga was dark blue green in colour, growing in clusters at the bottom of the stream. Individual filaments were blue green to olive green in colour. Mature trichome straight, cells much broader than long with distinct cross walls. Apical cells hemispherical with keritomized content. Individual cells were round in shape and the size varies from 57.60μm to 69.05μm in width and 5.20μm to 9.55μm in length thus the ratio of length and breadth as 1:8. When such cells were stacked one above the other it gives "stack of poker chips" appearance, characteristic feature of the species. Notches were found at the inner side of the cell corresponding to the slit on the trichome. When such cells were stacked one above the other, it results in the crack like appearance on the trichome. One to three notches/slits were observed in the present study. Reproduction both by fragmentation and hormogonia (formation of separation disc) was observed.

Application/Improvements: The new finding like cracks/ slit like structure on trichome can be taken for further studies. The microphotographs will enable the researchers to have better understanding.