Patrick 1945 Category: Symmetrical biraphid
BASIONYM: Caloneis lewisii Patrick 1945
REPORTED AS: Caloneis schumanniana (Grunow) Cleve (Krammer & Lange-Bertalot 1986, Fig. 171: 4)
The valve margin is triundulate, with the central undulation being slightly broader than the distal undulation. The apices are broadly rounded to cuneate. The axial area is narrow, becoming apiculate toward the apices. The central area is large and rhomboidal in shape with two lunate markings within the central area, on each side of the central nodule. The raphe is straight and filiform near the distal and proximal ends, becoming slightly lateral between them. Proximal raphe ends are slightly expanded. Striae are parallel, becoming radiate toward the central nodule and slightly divergent at the ends.
Krammer and Lange-Bertalot (1986) illustrate a very broad concept of C. schumanniana (Grunow) Cleve which includes C. lewisii. For the US flora, the shape and size series of C. lewisii is treated as distinct at the species level.
Basionym: Caloneis lewisii
Author: Patrick 1945
Length Range: 27 µm
Width Range: 8.7 µm
Striae in 10 µm: 19-20
Valvae bis constrictae longae 27 µ ad medium 8.7 µ apicibus cuneatae ; striis transversis 19-20 in 10 µ ; area axiali angusto, nodulo centrali majusculo subquadrangularis signis lunatis duobus crasso. Type: Illinois, Du Page County, 2423 F. Drouet, P. C. Standley and J. A. Steyermark (A-2018).
Patrick, R.M. (1945). A taxonomic and ecological study of some diatoms from the Pocono Plateau and adjacent regions. Farlowia 2(2):143-221.
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.
Caloneis lewisii thrives in a wide variety of environments ranging from flowing streams to small lakes and ponds in the midwestern U.S., including shallow, temporary waters.