Biremis undulata

(P.Schulz) N.A.Andresen, Edlund and N.Soninkhishig 2001      Category: Symmetrical biraphid
BASIONYM: Caloneis baltica var. undulata P.Schulz 1926
SYNONYM(S): Oestrupia zachariasii var. undulata (Schulz) Stoermer and Yang 

Biremis circumtexta


Boreozonacola hustedtii

LM scalebar = 10 µm = 80 pixels.


Contributor: Mark Edlund | David R.L. Burge - June 2017
Length Range: 24-31 µm
Width Range: 8.1-8.7 µm
Striae in 10 µm: 11.9-12.5


Valves are linear-lanceolate, with a tri-undulate margin. The central undulation is the broadest point of the undulations. Apices are cuneate. The axial area is linear and narrow. The central area is slightly expanded, to round in larger specimens. Each stria is composed of three transapically elongate openings (with the most distal often placed on the valve mantle). The distal two openings are connected by an alveolate chamber that forms a marginal longitudinal line. Striae are parallel in the central valve and radiate toward the valve ends. The raphe is straight and filiform, with straight proximal ends. Distal raphe ends are both hooked to the same side.

Original Description

Basionym: Caloneis baltica var. undulata
Author: P.Schulz 1926
Length Range: 36 µm
Width Range: 11 µm
Striae in 10 µm: 10-11

Original Description

Var. undulata n.v. (Fig. 77). - Schalen linear-elliptisch mit undulierten Seiten und deutlich keilförmigen Enden. Streifen aus transapikal verlängerten Punkten bestehend, die 3 wellige Längslinien bilden. Punkte der inneren Reihen besonders stark verlängert. Randlinien nicht besonders deutlich, dicht am Schalenrande. Grösse 36 : 11 µ, Str. 10 - 11. Heiternest (49 - 52 m).

Original Images

Cite This Page:
Edlund, M., and Burge, D. (2017). Biremis undulata. In Diatoms of the United States. Retrieved April 21, 2018, from

Species: Biremis undulata

Contributor: Mark Edlund | David R.L. Burge

Reviewer: Sarah Spaulding


Andresen, N.A. and Stoermer, E.F. (1978). The diatoms of Douglas Lake—a preliminary list. The Michigan Botanist 17: 49-54.

Edlund, M.B, Andresen, N. and Soninkhiskig, N. (2001). Morphology of Oestrupia zachariasii and its transfer to Biremis. Diatom Research 16: 295-306. 10.1080/0269249X.2001.9705521

Schulz, P. (1926). Die Kieselalgen der Danziger Bucht mit Einschluss derjenigen aus glazialen und postglazialen Sedimenten. Botanische Archiv 13: 149-327.

Stoermer, E.F. (1978). Diatoms from the Great Lakes. I. Rare or poorly known species of the genera Diploneis, Oestrupia and Stauroneis. Journal of Great Lakes Research 4 (2): 170-177 . 10.1016/S0380-1330(78)72181-7

Stoermer, E.F. (1980). Characteristics of benthic algal communities in the upper Great Lakes. U.S. Environmental Protection Agency, Ecological Research Series, EPA 600/3-80-073. Environmental Research Laboratory, Duluth, Minnesota. 72 pp.

Stoermer, E. F. and Yang, J. J. (1969). Plankton diatom assemblages in Lake Michigan. Univ. Michigan, Great Lakes Res. Div. Spec. Rep. No. 47, 168 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Biremis undulata CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Biremis undulata is a truly rare diatom and has been reported only a handful of times in North America. It appears limited in its distribution to benthic habitats in oligotrophic to mesotrophic lake systems. In North America it has been reported from northern Lake Michigan and large inland lakes of Michigan’s northern lower peninsula (Stoermer & Yang 1969, Anderesen & Stoermer 1978, Stoermer 1978, 1980, Edlund et al. 2001).