Nitzschia filiformis
(W. Smith) Schütt 1896 Category: Nitzschioid
BASIONYM: Homoecladia filiformis W. Smith 1856
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Pat Kociolek - September 2011
Length Range: 27.0-150.0 µm
Width Range: 4.0-5.0 µm
Striae in 10 µm: 29-34
Description
The valves are linear to linear-lanceolate, with apices acutely rounded. The raphe keel is not positioned on the margin, but slightly off the margin. Fibulae are distinct, irregular in size, and relatively broad and with a density of 7-9 in 10 µm. A prominent central nodule is present. Striae are indistinctly punctate and fine, but visible under LM.
Original Description
Basionym: Homoecladia filiformis
Author: W. Smith 1856
Length Range: µm
Striae in 10 µm:
Original Description
Original Images
Cite This Page:
Kociolek, P. (2011). Nitzschia filiformis. In Diatoms of the United States. Retrieved May 24, 2013, from http://westerndiatoms.colorado.edu/taxa/species/nitzschia_filiformis
Species: Nitzschia filiformis
Contributor: Pat Kociolek
Reviewer: Loren Bahls
Image Credit: Pat Kociolek
- Valves linear or slightly sigmoid
- Prominent central nodule
- Fibulae irregularly spaced and sized
- Fibulae positioned slightly off valve margin
The valves are generally linear but can also be slightly sigmoid, especially in smaller specimens. The central nodule is prominent. The fibulae are irregularly spaces and sized. At the central area, the fibulae are positioned slightly off of the valve margin.
Compare
Nitzschia filiformis is less strongly curved than N. sigma. The apices of N. filiformis are less constricted than those in either N. clausii or N. sigma. The linear valve with prominent fibulae make this species easily recognizable from other common species of the genus. Nitzschia filiformis has valves that are more linear than those of N. nana, and its apices are also more broadly rounded.
Nitzschia sigma
Nitzschia clausii
Nitzschia nana
Grunow in Van Heurck
Citations
Krammer, K. and Lange-Bertalot, H. (1988). Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/2. Gustav Fisher Verlag, Jena.
Smith, W. (1853). Synopsis of British Diatomaceae. John Van Voorst, London 1853. 89 pp., pls 1-31.
Van Heurck, H. (1896). A Treatise on the Diatomaceae. Translated by W.E. Baxter. William Wesley & Son, London. 558 pp., 35 pls.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 48145