Fragilariopsis
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| Class BACILLARIOPHYCEAE Subclass BACILLARIOPHYCIDAE Order BACILLARIALES Family Bacillariaceae Genus Fragilariopsis Hustedt This genus unites its cells into ribbon-shaped colonies. In girdle view, the cells look linear. In valve view, they are linear-elliptical-lanceolate. They can be heteropolar (one apex is narrower than the other), but this is mostly evident in larger specimens. Transapical costae separate transapical rows of areolae. There are usually two rows of areolae between any two costae5. This genus is closely related to the genera Nitzschia and Pseudonitzschia. The differences are mainly in colony forms and cell shape. Fragilariopsis has a tendency towards heteropolarity along the apical axis - a feature not seen Nitschia9. Look for the valve outline - is the specimen wide or narrow, relation between the apices (heteropolar?), degree of deviation from linearity - how far from the middle does the outline stop being linear?5, 9. |
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Suggestions or comments? Mail Simon H.H. Nielsen at Simon@npolar.no |