The Characterization of Hyalochlorella marina gen. et sp.nov. a New Colourless Counterpart of Chlorella

SUMMARY: Hyalochlorella marina is described as the type species of a new colourless genus of the chlorococcalean algae. It is a morphological and developmental counterpart of Chlorella and analogous to Prototheca, the known colourless counterpart. Hyalochlorella is distinguishable from Prototheca by its mode of autospore discharge, its possession of a large centric or eccentric vacuole, a Ruthenium Red positive wall and its lack of pectinaceous interstitial ground substance in the mature sporangium. Its developmental cycle is simple, involving a period of growth followed by cytokinesis. Nuclear division occurs concomitantly with growth; cytokinesis involves the segmentation of a multinucleate protoplast into uninucleate daughter protoplasts (pre-autospores) by simultaneous multiple fission. Daughter cell number, although variable, is usually an integral of 2n or 2n--2n-2. Numbers in the 2n--2n-2 series are believed to result from the degeneration of one nucleus in the tetranucleate stage followed by subsequent growth and division.