Hemiselmis
- Hemiselmis brunnescens Butcher (ref. ID; 474, 3715)
- Hemiselmis rufescens Parke (ref. ID; 474, 3715)
- Hemiselmis virescens Droop (ref. ID; 474, 3715)
Descriptions
Cell of H. brunnescens are ovate or bean-shaped, slightly laterally compressed, 5.5x3.0x3.0 um in size. A shallow "rudimentary gullet" divides the cell into two, the anterior to posterior length ratio being approximately 2:3. There are two unequal flagella approximately 5.0 and 7.0 um in length respectively, directed towards the anterior. The chromatophore is orange-brown in color, giving thick cultures a distinctly brown appearance which distinguished them from H. rufescens cultures which a pink and H. virescens Droop cultures which are blue-green in colour. (ref. ID; 474)
In H. brunnescens the longer flagellum ranges in size from 6.3-8.6 um and the shorter 4.3-6 um. (ref. ID; 3715)
Comments
The longer flagella in H. brunnescens and H. virescens bear two rows of mastigonemes 1.4-2 um in length, each of which terminates in a filament 0.7-1.2 um long. In addition to mastigonemes, the long flagella bear narrower short filaments 0.4 um in length. The shorter flagella bear a single row of mastigonemes 1.2-1.6 um in length, each with a terminal filaments 0.6-0.8 um long. At the base of the long flagellum is a tuft of mastigonemes comprising 8-24 filaments, 12 being the most common number encountered. These mastigonemes are identical with those on the long flagella. The surfaces of the long and short flagella in both species are covered with an imbricated layer of extremely fine scales. These are about 17 nm in diameter and are 7-sided. Each of the 7 sides corresponds to a tangentially elongated foramen separated from its neighbours by narrow wall. The overall lace-like structure of the scales seems to be based upon a helically arranged series of foramena of decreasing size towards the centre, which is occupied by a boss. (ref. ID; 3715)
Descriptions
In H. virescens the longer flagellum is 6.3-8 um and shorter 4.6 to 5.8 um. (ref. ID; 3715)