Pinnularia polyonca
(Brébisson) W. Smith 1856 Category: Symmetrical biraphid
BASIONYM: Navicula polyonca Brébisson in Kützing 1849
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Loren Bahls - March 2012
Length Range: 68-80 µm
Width Range: 8.9-10.3 µm
Striae in 10 µm: 10-12
Description
Valves are rhombic-lanceolate with a triundulate outline, the middle expansion is wider than the distal ones. Apices are capitate and rounded. The axial area is very wide and lanceolate in shape. The central area is a transverse fascia. In some populations, there are one or two short striae on the secondary side of the fascia. The raphe is lateral. Proximal raphe ends are curved to the primary side. Terminal raphe fissures are shaped like question marks. Striae are very short and radiate in the middle, becoming longer and strongly convergent towards the apices.
Original Description
Basionym: Navicula polyonca
Author: Brébisson in Kützing 1849
Length Range: µm
Striae in 10 µm:
Original Description
Original Images
Cite This Page:
Bahls, L. (2012). Pinnularia polyonca. In Diatoms of the United States. Retrieved May 25, 2013, from http://westerndiatoms.colorado.edu/taxa/species/pinnularia_polyonca
Species: Pinnularia polyonca
Contributor: Loren Bahls
Reviewer: Sarah Spaulding
Image Credit: Loren Bahls
- Valves triundulate
- Apices capitate
- Axial area broad, lanceolate
- Central fascia
Valves are triundulate with the broadest portion in the middle. Apices are capitate. The axial area is broad and lanceolate, merging with a central transverse fascia.
Compare
Pinnularia formica has a much more exaggerated triundulate outline, with a more prominently expanded central margin.
Pinnularia formica
(Ehrenberg) Patrick 1966
Citations
Krammer, K. (2000). The genus Pinnularia. The Diatoms of Europe. Diatoms of Inland Waters and Comparable Habitats 1: 1-703.
Kützing, F.T. (1849). Species Algarum. Lipsiae. F.A. Brockhaus, 922 pp.
Smith, W. (1856). Synopsis of British Diatomaceae. John Van Voorst, London 1856. 2: 107pp., pls. 32-60, 61-62, A-E.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 52087
Autecology Discussion
Pinnularia polyonca has been found in two small lakes and a floating-mat fen in western Montana. All three sites have abundant vascular plant growth. The pH of these sites ranges from 6.73 to 7.41 and specific conductance ranges from 22 to 257 µS/cm.
Images
Skinner Lake, Beaverhead National Forest, Montana: home of Pinnularia polyonca.
Credit/Source: Loren Bahls