Planothidium biporomum differs from other Planothidium species with a cavum, such as P. frequentissimum and P. potapovae, by the lanceolate valves with capitate ends. Planothidium incuriatum has subrostrate apices. Planothidium haynaldii has a depression, but not a cavum, on the internal surface of the central area. Planothidium sheathii has obtusely rounded, but not protracted apices. Rapheless valves should also be observed to confirm identification.
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.