Silva Center for Phycological Documentation: Index Nominum Algarum

The INA is a card file and online reporting system maintained at the Silva Center for Phycological Documentation of the University Herbarium, University of California, Berkeley. It contains nearly 200,000 names of algae (in the broad sense). The BPU is a card file containing bibliographic references pertaining to algal taxonomy.
A working list of algal type specimens at UC is available here

Results from INA database

Synedra tenera f. acicularisA. Cleve-Euler image
Synedra tenera var. hinganicaB.V. Skvortzov image
Synedra tenera var. lanceolataE.V. ěstrup image
Synedra tenera var. sinicaSkvortzov Publ. Mus. Hoangho Paiho Tien Tsin 36: 18, pl. 4: fig. 8 1935
Synedra teneraW. Smith image