Portrait of Haematococcus pluvialis (Flotow, 1844), a widely distributed volvocid flagellate. Thin cytoplasmic strands traverse the clear mucilaginous layer to connect the protoplast to the spherical cell wall. Single large cup-shaped chloroplast. Two equal-length flagella are also seen traversing the mucilaginous layer. Reddish carotenoid pigments may obscure the stigma and chloroplast. From fish farm aquaculture pond near Boise, Idaho. Phase contrast.