Sellaphora bacillum

(Ehrenberg) D.G. Mann 1989      Category: Symmetrical biraphid
SYNONYM(S): Diadesmis bacillum (Ehrenberg) Kützing 1844 | Pinnularia bacillum (Ehrenberg) Ehrenberg 1876 | Schizonema bacillum (Ehrenberg) Kuntze 1898 

Sellaphora bacilloides


Sellaphora californica

LM scalebar = 10 µm = 40 pixels.


Contributor: Pat Kociolek - March 2011
Length Range: 30-45 µm
Width Range: 9-10 µm
Striae in 10 µm: 12-14


Valves are linear-elongate with rounded apices. The axial area is straight and bordered by a distinct hyaline conopeum. The raphe is straight with rounded and slightly dilated proximal external ends. The distal ends are deflected onto the margin. T-shaped thickenings are present, but indistinct, near the ends. Striae are radiate and arched, becoming parallel at the apices. Striae are broadly spaced at the center of the valve, and become finer (to 22 in 10 µm) at the ends.

Cite This Page:
Kociolek, P. (2011). Sellaphora bacillum . In Diatoms of the United States. Retrieved October 20, 2016, from

Species: Sellaphora bacillum

Contributor: Pat Kociolek

Reviewer: Rex Lowe


Jahn, R., Mann, D.G., Evans, K.M. and Poulíčková, A. (2008). The identity of Sellaphora bacillum (Ehrenberg) D.G. Mann. Fottea 8: 121–124.

Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.

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.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Sellaphora bacillum CAS

NCBI Genbank Taxonomy

Sellaphora bacillum NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 170009

Autecology Discussion

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Sellaphora bacillum

EMAP Response Plots

Sellaphora bacillum

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.