Type 3 Trebouxiophyceae

The single isolate of Type 3 is a very small, slightly elliptical coccoid. The cup-shaped plastid generally fills less than half the cell. A small pyrenoid-like structure is present. If this is a pyrenoid, there is no significant starch sheath. Two to four autospores are produced. Cells range from about 2-4 µm in the long axis.

Type 3 Green coccoid can be distinguished from other trebouxiophytes by the HaeIII fragments. These fragments differ only very slightly from Type 4.   The gel on the left shows the HaeIII fragments from both Type 3 (left) and Type 4 (right).   TaqI fragments clearly distinguish Type 3 from Type 4. We have found only a single isolate of Type 3, JL2/4 from Jim Lake, North Dakota., isolated from a plankton sample taken 2/03/95.