Compare

Fallacia californica and F. tenera are similar in size and in their coarse areolae. However, F. tenera has a narrower lanceolate lyre-shaped hyaline area, uniform striae along the valve margin (particularly near the central area), a symmetric central area and a single or incomplete double row of areolae along the raphe. Fallacia cryptolyra and F. sublucidula are also small freshwater species with distinct panduriform lyre, but they have fine areolae that are not resolvable in LM.

LM scalebar = 10 µm
Fallacia Californica Swamp 404 S 25668 004 Fallacia Californica Swamp 404 S 25668 003 Fallacia Californica Swamp 404 S 25668 001 Fallacia Californica Swamp 404 S 25668 002 Fallacia Californica Swamp 404 S 25668 005
Length Range
6–15 µm
Width Range
3.5–5.6 µm
Striae in 10 µm
20-23

Fallacia tenera

(Hust.) D.G.Mann in Round et al. 1990

Fallacia Tenera 901 M14126 2 Fallacia Tenera 901 M14126 Fallacia Tenera 519 Ps0765 04132016 02 Fallacia Tenera 519 Ps0765 04132016 03
Length Range
9.4-15 µm
Width Range
4.5-7 µm
Striae in 10 µm
16-21

Also compare to

Fallacia cryptolyra

BioData Reference
Krammer and Lange-Bertalot 2/1 Pl 65 Fig 7-9