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Pinnularia divergentissima

(Grunow) Cleve 1895      Category: Symmetrical biraphid
BASIONYM: Navicula divergentissima Grunow in Van Heurck 1880

REPORTED AS: Pinnularia martinii f. martinii (Krasske 1939) | Pinnularia fottii (Bily & Marvan 1959) 

Pinnularia brebissonii


Pinnularia gigas

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - December 2011
Length Range: 28-46 µm
Width Range: 5.0-7.0 µm
Striae in 10 µm: 12-14


Valves are linear to linear-lanceolate with obtusely rounded, subrostrate apices. The axial area is narrow and linear. The central area is a broad fascia reaching the valve margins. Raphe branches are filiform and straight. Proximal raphe ends are small, deflected to one side, and close to one another. Terminal raphe fissures are hooked. Striae are extremely radiate near the valve center and become extremely convergent about half way to the apices. The change in striae direction is sudden, forming an acute angle between the two striae groups where they meet.

Original Description

Basionym: Navicula divergentissima
Author: Grunow in Van Heurck 1880
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2011). Pinnularia divergentissima. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Pinnularia divergentissima

Contributor: Loren Bahls

Reviewer: Sarah Spaulding


Camburn, K.E. and Charles, D.F. (2000). Diatoms of Low-Alkalinity Lakes in the Northeastern United States. Academy of Natural Sciences of Philadelphia, Special Publication 18, 152 pp.

Cleve, P.T. (1895). Synopsis of the Naviculoid Diatoms, Part II. Kongliga Svenska-Vetenskaps Akademiens Handlingar 27(3):1-219.

Krammer, K. (1992). Die Gattung Pinnularia in Bayern. Hoppea 52: 1-308.

Krammer, K. (2000). The genus Pinnularia. The Diatoms of Europe. Diatoms of Inland Waters and Comparable Habitats 1: 1-703.

Lange-Bertalot, H., Kulbs, K., Lauser, T., Norpel-Schempp, M. and Willmann, M. (1996). Diatom taxa introduced by Georg Krasske: Documentation and revision. Iconographia Diatomologica (H. Lange-Bertalot, ed.), Vol. 3, Koeltz Scientific Books, Konigstein, 358 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.

Van Heurck, H. (1880). Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Pinnularia divergentissima CAS

North American Diatom Ecological Database (NADED)

NADED ID: 52027

Autecology Discussion

Pinnularia divergentissima has been recorded from 12 creeks, ponds, and small lakes in the Northwest United States. In these waters mean pH is 7.4, mean specific conductance is 41 μS/cm, and common diatom associates are Neidium bisulcatum, Cymbopleura subrostrata, Denticula valida, Caloneis leptosoma, and Eunotia praerupta. Elsewhere in the U. S., this species has been reported from Ohio and Wyoming (Patrick & Reimer 1966) and from low-alkalinity lakes in New York (Camburn & Charles 2000). Patrick & Reimer (1966) report that it prefers cold water and is often found in mountainous country. Krammer (2000) reports this species as cosmopolitan in northern alpine zones, particularly on mosses in forests, in meadows, or in waters with low electrolyte content.


Paradise Pond, Glacier National Park, Montana: home of Pinnularia divergentissima.

Credit/Source: Loren Bahls

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

Pinnularia divergentissima

EMAP Response Plots

Pinnularia divergentissima

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.