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

Amphora acuta var. arcuata(A. Schmidt) P.T. Cleve image
Amphora acuta var. japonicaB.V. Skvortzov image
Amphora acuta var. labyrinthica(A. Grunow) P.T. Cleve image
Amphora acuta var. mediaHeiden Mitth. Mecklenb. Geol. Landesanst. 10{21}: 3, fig. 3 1900
Amphora acuta var. minorN. Foged image
Amphora acuta var. neogenaJ. Pantocsek image
Amphora acuta var. parvaA.H. Wachnicka & E.E. Gaiser Diatom Research 22: 410, 447, figs. 77-79 2007
Amphora acutaW. Gregory image