Taxon Account

Ctenophora (Grunow) Williams & Round; 1986; 330

Key references

Williams D.M., Round F.E. 1986. Revision of the genus Synedra Ehrenb. Diatom Research. 1(2): 313-339.


Cells spicular, linear to linear lanceolate in valve view, with rounded, protracted, rostrate to subcapitate ends; cells lying in valve or girdle view.

Isovalvar, isopolar, bilaterally symmetrical.

Striae uniseriate, parallel, perpendicular to apical axis, distinctly punctate in LM; areolae circular or almost rectangular, aligned apically as well as transapically (‘orthostichous’ striae), occluded externally by cribra. At each end there is a rimmed area (apical pore field) of closely spaced, small, unoccluded pores; adjacent to the pore field there is a single rimoportula.

Axial area narrow, linear. Central area large, rounded or rectangular extending to both valve margins (forming a fascia), hollow on the inside, creating a lens-like appearance in LM.

Girdle structure unknown.

Chloroplasts large, plate-like (number unknown).

Cells usually forming tuft-like colonies attached to surfaces by individual mucilage pads secreted through the apical pore fields, or by a massive compound sheet of mucilage produced by a line of several or many adjacent cells (derived from a single cell by repeated division).


References are given in chronological order.

Williams D.M., Round F.E. 1986. Revision of the genus Synedra Ehrenb. Diatom Research. 1(2): 313-339. Morphology; Taxonomy; Description; Type Illustration; Illustrations
Round F.E., Crawford R.M., Mann D.G. 1990. The Diatoms. Biology & Morphology of the Genera. Cambridge University Press, Cambridge. 747 pp Morphology; Illustrations
This page should be cited as:

Mann D. G. Ctenophora (Grunow) Williams & Round; 1986; 330. In: Jüttner I., Carter C., Chudaev D., Cox E.J., Ector L., Jones V., Kelly M.G., Kennedy B., Mann D.G., Turner J. A., Van de Vijver B., Wetzel C.E., Williams D.M.. Freshwater Diatom Flora of Britain and Ireland. Amgueddfa Cymru - National Museum Wales. Available online at [Accessed:  ].

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Record last modified: 27/12/2020