Glossary terms starting with "I"
Interfascicule - costa
Usually applied to centric diatoms, the interfasciular area is the unornamented, thicked rib of silica located between fascicles.
Intermissio
Fissure that joins the proximal raphe ends in some cymbelloid taxa. Instead of distinct termination of the proximal raphe ends, they are connected, internally by a fissure.
Isopolar
Valves that are symmetrical to the transapical axis are termed 'isopolar'. The poles of these valves are similar in shape and size.
Isotype
An isotype is any duplicate of the holotype; it is always a specimen.