DESMIDS OF THE GENUS MICRASTERIAS
FROM AUSTRALIA'S TROPICAL NORTH.
M. DINGLEY (AUSTRALIA).
Micrasterias are some of the largest and most beautiful of all desmids. Some are quite simple in outline whilst others can be extremely ornate. They are characterised by their relatively flat disc-like and deeply incised lobes.
On a recent trip to Australia's tropical north I collected many freshwater samples and have been lucky enough to find some rather exquisite Micrasterias species and thought they might be of interest to readers.
Comments to the author, Mike Dingley, are welcomed.
|
Micrasterias anomala This is a very anomalous and extraordinary plant of which there are several varieties. It has similarities with Xanthidium armatum and Micrasterias americana. |
|
|
Micrasterias ceratofera This is a stunningly beautiful desmid. Its simple form and long spinous processes make this unmistakable in any sample. |
|
|
Micrasterias foliaceae The cells of this Micrasterias are square in outline and joined together to form filaments up to 182 cells long. The apex has a peculiar arrangement of large teeth which interlock with each other. |
|
|
Micrasterias lux First described by William Joshua from Rangoon in 1886 this desmid has 4 lobes subdivided, slightly inflated at the base, much attenuated and deeply furcate at their ends. |
|
| Micrasterias crux-melitensis
This is a nicely proportioned Micrasterias having wide spaces between the lobules which are tipped with 2 spines. There is some confusion between this species and M. radians with the latter differing in having somewhat longer lateral lobes and longer apical lobes. Some authors consider them separate species whilst others consider M. radians a variety of M. crux-melitensis. |
|
|
Micrasterias thomassiana var. notata Brightfield This is quite a large and imposing cell having bidentate extremities. This particular variety differs from other varieties in its lack of surface spines and no supraisthmal processes. |
|
|
Micrasterias thomassiana var. notata Phase Contrast The same cell as that above is shown here in phase contrast. |
|
|
Micrasterias truncata These cells are quite small compared to some of the others above. There appear to be many different varieties and forms. |
|
