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Navicula freesei

R.M.Patrick and Freese      Category: Symmetrical biraphid

Navicula flatheadensis


Navicula galloae

LM scalebar = 10 µm = 40 pixels.


Contributor: Paul Hamilton - December 2011
Length Range: 62-77 µm
Width Range: 13.3–15.2 µm
Striae in 10 µm: 8–9


Valves are lanceolate with rounded rounded apices. Striae are radiate at the center, to parallel and slightly convergent at the apices. The central area is asymmetrically rounded, while the axial area is narrow and straight. Striae on one, or both, sides of the central area are irregularly spaced. The raphe is lateral and straight. The distal raphe fissures form curved hooks onto the mantle. The proximal raphe ends form an elongated central poroid. Areolae are distinct and linear, 22-24 in 10 µm. A thickened central nodule is evident. Girdle bands are not yet defined.

Original Description

Author: R.M.Patrick and Freese 1961
Length Range: 52–78 µm
Width Range: 12–15 µm
Striae in 10 µm: 5 in the center valve, 8–10 in the rest of valve

Original Description

Navicula freesei sp. nov. Pl. 2, Fig. 14

Valva lanceolata valide, attenuata ad apices rotundatos. Haec species attenuata apicum dat valvae formam propriam. Area axiali angusta, distincta. Area media rotundata, asimili aliquantulum. Striis translineatis, radiatis per maximam partem valvae, apicibus leniter sed definite convenientibus. Striis sepositis plus procul circum aream mediam. Striis 5 in 10 µ ad aream mediam, 8-10 in 10 µ in reliqua valva. Longitudo, 52-78 µ. Latitudo, 12-15 µ. Valve strongly lanceolate, attenuated to the rounded ends. This attenuated appearance of the ends gives the valve a characteristic shape. Axial area narrow, distinct. Central area rounded, more or less asymmetrical. Striae cross-lineate, radiate throughout most of the valve, at the ends slightly but definitely convergent. Striae more distantly spaced about the central area. Striae 5 in 10 µ at central area, 8-10 in 10 µ. in rest of the valve. Length, 52-78 µ. Breadth, 12-15µ.

This taxon is similar to Navicula hasta var. gracilis Sky. (Philippine Jour. Sci., 61: 275, pl. 7, fig. 9, 1936) in shape of valve, structure of axial and central areas, and number of striae. It differs in the striae which in this taxon are slightly convergent at the ends whereas in Skvortzow’s taxon they are radiate throughout the valve, and the length-to-breadth ratio is a little less in this taxon. This taxon is also similar to N. peregrina var. peregrinoides (A. Cl.) Cl.-Eul. (K. Svenska Vet.-Akad. Handl., ser. 4, 4 (5) : 149, 1953) from which it differs by its smaller size and shape of the central area. Occurrence in collection fairly numerous.

This taxon is named in honor of Dr. Leonard R. Freese who collected most of the diatoms considered in this paper and is co-author of the paper. Specimen illustrated.-Station 72 (A-G.C. 8188A) . Holotype.

Type locality.−Alaska, Sec. Jud. Div., pool on edge of Saltwater Lake, Pt. Barrow Camp. Coll. L. R. Freese, 14 July 1951.

Distribution.—GEOGRAPHICAL—In addition to the type locality, found also at Stream No. 2, Station 46, Coll. L. R. Freese, 30 June 1951 (A-G.C. 8162) ; Stream No. 2, Station 77, Coll. L. R. Freese, 14 July 1951 (A-G.C. 8193) . ECOLOGICAL-Fresh to brackish water. Holotype from pool on edge of Saltwater Lake. pH, 7.8; temp., 6° C. Other specimens from pool in bed of stream and from edge of stream flowing into lagoon. pH, 6.8; alk., 20 ppm (as CaCO3) ; hardness, 27 ppm (as CaCO3) ; Cl, 14 ppm; total Fe, 0.21 ppm.

Original Images

Cite This Page:
Hamilton, P. (2011). Navicula freesei. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Navicula freesei

Contributor: Paul Hamilton

Reviewer: Sarah Spaulding


Patrick, R.M. and Freese, L.R. (1961). Diatoms (Bacillariophyceae) from Northern Alaska. Proceedings of the Academy of Natural Sciences of Philadelphia 112(6):129-293.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Navicula freesei CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion