(Kützing) Meister 1912 Category: Monoraphid
BASIONYM: Cymbella flexella Kützing 1844
SYNONYM(S): Achnanthes flexella (Kützing) Brun
Contributor: Marina Potapova - October 2010
Length Range: 18-40 µm
Width Range: 9-20 µm
Striae in 10 µm: 22-24 in center valve
Frustules are strongly bent in girdle view with concave raphe valve and convex rapheless valve. Valves are elliptical-lanceolate with slightly drawn-out ends and deep mantles. Valve face has depressions along the margins. The raphe valve has a narrow axial area and a lanceolate-rhomboid central area. The raphe is straight or slightly sigmoid with terminal ends sharply turned to opposite directions. Rapheless valve has a narrow linear or slightly sigmoid axial area and a large rectangular or hexagonal central area. The striae are punctate, strongly radiate on raphe valve and slightly radiate on rapheless valve, 22-24 in 10 μm.
Basionym: Cymbella flexella
Author: Kützing 1844
Length Range: 41 µm
Striae in 10 µm:
CYMBELLA? FLEXELLA. Taf. 4. Fig. XIV, Taf. 6. Fig. VIII. (420/1). C. laevissima, mi¬nor, a latere secundario elliptica, subsigmoidea, apicibus parum productis obtusis, altero latere cur-vata, (genuflexa) dorso convexo, ventre concavo exciso, apice truncato. In Quellwasser bei Thun in der Schweiz! — Länge 1/55”’.
Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.
Meister, F. (1912). Die Kieselalgen der Schweiz. Beiträge zur Kryptogamenflora der Schweiz, 4/1, 1–254.
Sampling for 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). Streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming). Over 1200 sites on 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.
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.