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Guide to Cocconeis czarneckii

Stancheva, D.L.Mora and R.Jahn 2022

Cocconeis czarnecki guide
  1. Raphe valve with narrow axial area
  2. Raphe valve with radiate striae
  3. Rapheless valve with more than 6 longitudinal line per hemivalve
  4. Rapheless valve with strongly radiate striae, curved near the apices

The raphe valve has a narrow axial area, a small elliptic central area, and a straight to slightly deflected filiform raphe. Striae are slightly radiate at the center to strongly radiate and curved toward the apices. Striae are interrupted by a hyaline, submarginal ring with uneven margin. The valvocopula is open, irregular, and finely fimbriated.

The rapheless valve has striae that are slightly radiate at the center, to strongly radiate and curved toward the apices. Areolae are short and dash-like and form 8–21 undulating longitudinal lines per hemivalve.