Genus: Without gelatinous sheath; without branching; filaments consist of many cells; planktonic; cell body cylindrical, apex of terminal cells rounded; septum slightly constricted; a parietal chloroplast plate-like with one or two pyrenoids (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species:

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Gloeotilopsis planctonica Iyengar & Philipose: Thalli unbranched, short filaments clearly constricted at the cross wall, without mucilaginous sheath; cell body elontate cylindrical, 3-5 micron broad at the cross wall, 4-7 micron broad at the mid region of the cell; 8-24 micron long; chloroplasts a single, parietal, usually occupying the entire length of the cell; with 1-2 pyrenoids; (Photomicrog. Freshw. Alg. 13: 21, 1994)