Desmids Multiplying by Dividing
by
William Ells
Coniferae, Walnut Tree Lane, Loose,
Maidstone, Kent, ME15 9RG, UK.
Most desmid cells of the order Placodermae can be seen to be divided into two distinct semi-cells; one of the exceptions is the genus Closterium. This genus can often be found multiplying asexually by division.
Fig .1 shows a cell in the early stages of division where a constriction has formed near the centre of the cell. The longest semi-cell is 210 mm. long the other 178 mm. This constriction proceeds somewhat like the closing of an iris diaphragm (Brook 1981). | |
Fig.2 shows the two semi-cells have parted. | |
Fig.3 shows the two new cells nearing completion. | |
Fig.4 shows the rings which form every time division takes place, the length of this cell is 316 mm. width at its widest 38 mm. |
For a more detailed description of
Closterium division see The Biology of Desmids
1981 by Alan J Brook pages 104-108.
Comments and feedback to Bill Ells are welcomed.
Published in October 1998 Micscape Magazine.
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