Frickea lewisiana

(Grev.) Heiden 1906      Category: Symmetrical biraphid
BASIONYM: Navicula lewisiana Grev. 1863

Fragilariforma virescens


Frustulia amosseana

LM scalebar = 10 µm = 20 pixels.


Contributor: Carrie Graeff - March 2010
Length Range: 255-265 µm
Width Range: 45.0 µm
Striae in 10 µm: 22-24


Valve of Frickea lewisiana are linear-lanceolate with bluntly rounded apices. There is little relative variation in the lengths of specimens, which were 255.0-265.0 µm in length and 45.0 µm in breadth. The majority of the striae are perpendicular, but they become convergent near the apices. Striae are composed of small, round areolae. Striae density is 22-24 in 10 µm. The longitudinal ribs are complete and extend to the helictoglossa. At the central area, the ribs enclose the central nodule but do not fuse with it. Externally, both the proximal and distal raphe ends are T-shaped. The areolae on the valve face opposite the location of the helictoglossa are highly unorganized and sparse. The areolae around the relatively small, symmetrical central area are expanded transversely, several times the length of the typical areolae openings on the valve. Rows of poroids are present between the raphe and longitudinal ribs near the central area and apices.

Original Description

Basionym: Navicula lewisiana
Author: Grev. 1863
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Graeff, C. (2010). Frickea lewisiana. In Diatoms of the United States. Retrieved April 24, 2018, from

Species: Frickea lewisiana

Contributor: Carrie Graeff

Reviewer: Marina Potapova


Greville, R.K. (1863). Descriptions of new and rare Diatoms. Series VIII. Transactions of the Microscopical Society, New Series, London 11(3):13-21, pl. I.

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.

Schmidt, A. (-). (1874-1959). Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Frickea lewisiana CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion