Gloeococcus tetrasporus sp. nov. (Tetrasporales, Palmellaceae), from Colorado mountain lakes [Algae, description, new taxa, morphology]

A new species, Gloeococcus tetrasporus sp. nov., collected from mountain lakes, is described from unialgal culture. Vegetative cells are ellipsoid and Chlamydomonas -like, occur in tetrad complexes within the general colonial matrix, and exhibit slow, limited motility within the confines of the individual gelatinous matrices. The colonial matrix is amorphous and structureless, without a definite bounding layer. Colonies may reach several centimeters in size. Vegetative cells have a parietal cup-shaped chloroplast with a central-basal pyrenoid and a small, linear stigma, two contractile vacuoles, and two short flagella. Cell division is by eleutheroschisis in nonflagellate cells. After two divisions, four daughter cells are formed within the expanded parent wall that will become incorporated into the colonial matrix.