Rapheless valve

In the cell development of monoraphid pennate diatoms, a raphe is initially formed on both valves. The raphe of one valve is secondarily filled with silica, leaving a thickened axial rib. The other valve lacks a raphe and is termed the “rapheless valve”.

Alternative Term

pseudoraphe valve

The term pseudoraphe is used in much of the literature, including in Patrick and Reimer (1966).

PRV

The abbreviation for pseudoraphe valve, PRV, is used by Kingston in Wehr and Sheath (2003).

central sternum

The pseudoraphe is called the "central sternum" by some authors.

Citations

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Wehr, J. and Sheath, R.G. (2003). Freshwater Algae of North America: Ecology and Classification. Academic Press, 917 pp.