Picocystophyceae

This is one of the smallest green algae. This one occurs in vast numbers in Mono Lake, where it is also referred to as Mickey Mouse (see bottom left). Cells have one plastid (middle left) that divides (lower left of center and lower right) until there are two plastids - the cell then divides. Phase contrast microscopy. 

This tiny green alga often has two chloroplasts, and these cells were found within detrital material that had colonized a spponge that has been submerged in Mono Lake. Differential interference contrast optics.