Rossithidium pusillum is similar to A. rivulare in valve shape, but the terminal raphe fissures of R. pusillum are not distinct. Achnanthidium minutissimum valves are more linear or linear-elliptical in shape. Rossithidium nodosum has coarser striae but lacks the two irregularly broad striae in the center of the raphe valve.
Diatoms of North America is running a fundraising campaign to keep the servers in operation. We need you to reach our $25,000 fundraising goal.
If you use and appreciate DONA, make your DONAtion today.
For the Gift Designation, type "diatom" in the search box and select "Diatom Lab Research Fund". This is the designated fund for diatoms.org.