The colonies of Pleodorina sp. are always mobile and have a spherical to sub-spherical shape, consisting of 32-128 cells that are spaced apart within a uniform, clear, gelatinous colonial envelope. These cells are not interconnected by cytoplasmic strands. The colony cells are differentiated into purely vegetative cells and those capable of dividing to produce daughter colonies. Nearly all cells except four are reproductive, or about half are reproductive while the other half are vegetative. The cells themselves are spherical to ovoid in shape. Vegetative cells possess a cup-shaped chloroplast containing one pyrenoid, a large anterior eyespot, and two cilia of equal length with two contractile vacuoles at their base. In contrast, reproductive cells initially resemble vegetative cells but later develop a larger chloroplast containing multiple pyrenoids. As they mature, the eyespot and cilia of reproductive cells disappear.