Melosira Undulata Guide
Credit: Loren Bahls
  1. Cells large, cylindrical, and robust
  2. Striae conspicuous
  3. Mantle unevenly thickened
  4. Mantle rimoportulae evenly-spaced

Melosira undulata has large, robust, cylindrical frustules linked in long chains. Valves and mantles are conspicuously ornamented with rimoportulae and striae. A ring of evenly-spaced rimoportulae encircles the mantle near the valve/mantle interface. The mantle is unevenly thickened internally, giving an undulating appearance.