dcsimg

Comprehensive Description

    Description of Scottia
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    Cells large, at the middle divided into two semicells by means of a widely open, deep constriction. Semicells not alike: the one with an apical corona of 8 or 9 teeth we may call the upper, the other with a rounded smooth apex we call the lower one. (These terms are quite arbitrarily chosen only for the reason that they just "look so", and because we have to call them by different names.) Both semicells are somwhat obovate with an inflated basis tapering towards the apices; they have a whorl of 6 processes just below the apex, which in the upper semicell is strongly protruded, in the lower widely rounded. Another whorl of 10 processes is to be found - also in both semicells - near the isthmus, inserted at the most inflated point. In the upper semicell all processes are strongly curved upwards and in the lower semicell towards the upper semicell ("in the wrong direction"). All processes are hollow and furnished with a few acute spines on the outer margin at the region of the greatest curvature, and all processes terminate in three slightly divergent spines, of which the inner one is twice as long as the other two. Vertical view circular, at the outer margin with ten radiating processes which are denticulated at their ends; inside the margins with 6 similar processes and in the central area with 8-9 teeth arranged in a circle: this latter lacking in the vertical view of the lower semicell. Between the processes the cell-wall is smooth. (This does not mean that there should be no pores.) the shape of the chromatophores we have not been able to establish as to their details, but it seems that there are 6 or 5 axile longitudinal 'laminae' or 'bundles' from which pairs of fine extensions go into the processes of the lower whorl and single extensions into those of the upper whorl. The number of pyrenoids is not known, but in vertical view there sometimes can be seen one pyrenoid in each lamella, which are not connected at the central longitudinal axis.   This description from Gronblad and Kallio, 1954. A new genus and a new species among the desmids. Botaniska notiser, 2: 167-171. The single species at that time was S. mira. 
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    David Patterson
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    5697456