Ultrastructure of Coccomyxa antarctica Shunan Cao & Qiming Zhou, sp. nov. a–c cultured in BBM medium; d-f cultured in PDA medium. a, b mature autosporangium c, d Cup-shaped chloroplast e, f vegetative cell. Key: Ch: chloroplast; Cw: cell wall; Mit: mitochondria; N: nucleus; S: starch granules; Th: thylakoids. Scale bars: 0.5 μm(a, d); 0.2 μm (b, c, e, f).