Raphe
Definition
A longitudinal slit or canal in the valve of certain pennate diatoms that allows cytoplasmic streaming and active gliding movement across surfaces. Its presence or absence divides pennate diatoms into raphid and araphid groups.
Related terms
- Assemblage
- The full community of diatom taxa present in a sample. The relative frequencies and absolute counts of species in an assemblage reflect...
- Epitheca and hypotheca
- The two halves of the frustule. The epitheca (larger) fits over the hypotheca (smaller) like a lid over a box. During cell...
- Frustule
- The silica cell wall of a diatom, composed of two overlapping valves (epitheca and hypotheca). Frustules are taxonomically distinctive, chemically resistant to...
- Sporopollenin vs. biogenic silica
- Pollen and spore walls are made of sporopollenin (a highly resistant biopolymer). Diatom frustules are made of biogenic opaline silica (SiO2·nH2O), a...
- Valve and girdle band
- The valve is the flat face of each frustule half, carrying the species-specific pore patterns used for identification. The girdle band is...
Explained in
- Diatom Biology and TaxonomyA longitudinal slit or canal in the valve of certain pennate diatoms that allows cytoplasmic streaming and active gliding movement across surfaces. Its presenc...