(Hornemann) Dawson ex Ross and Sims 1978 Category: Asymmetrical biraphid
BASIONYM: Ulva olivacea Hornemann 1806
SYNONYM(S): Gomphonema olivaceum (Hornemann) Brébisson 1838
Contributor: Pat Kociolek - February 2011
Length Range: 14-40 µm
Width Range: 5-8 µm
Striae in 10 µm: 10-13 in the center of the valve, 12-14 at the ends
Valves are clavate with a broadly rounded headpole and a narrow footpole. The valve tapers more strongly towards the footpole than to the headpole. The raphe is filiform and lateral. The raphe terminates internally distantly from the apices. The axial area is narrow, straight, and expanded laterally to form a rectangular central area bordered by shortened striae at or near the margin. Stigma are absent. Striae are costate and individual areoale are not visible in the LM. Striae are radiate. The apical pore fields appear (with DIC optics) more like condensed striae rather than differentiated apical pore fields.
Although this species was validly transferred to Gomphoneis (Ross and Sims 1978) (also see Dawson 1974), this classification has not been uniformly recognized and continues to appear as Gomphonema olivaceum.
Comments: In the USA flora we recognize a more narrow concept than that suggested by Krammer and Lange-Bertalot (1986, pl. 165). The specimens illustrated in figs. 4-6 are similar to those in North America. Figures 1-3 appear to be of another taxon.
Basionym: Ulva olivacea
Author: Hornemann 1806
Length Range: µm
Striae in 10 µm:
Dawson, P.A. (1974). Observations on diatom species transferred from Gomphonema C.A. Agardh to Gomphoneis Cleve. British Phycological Journal 9: 75-82.
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. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Ross, R. and Sims, P.A. (1978). Notes on some diatoms from the Isle of Mull, and other Scottish localities. Bacillaria 1:151-168.
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.
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.