A Key to the More Frequently Occurring Freshwater Algae - Freshwater Algae: Identification, Enumeration and Use as Bioindicators - page 237

3a

2a 2b

3b

1a

1b

4

Plate XXVII 1. Pinnularia viridis : (a) surface markings, (b) chloroplasts. 2. Amphipleura : (a) surface markings (b)
chloroplasts. 3. Diploneis : (a) surface markings, (b) chloroplasts. 4. Frustulia.