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Sellaphora laevissima

(Kütz.) D.G.Mann 1989      Category: Symmetrical biraphid
BASIONYM: Navicula laevissima Kütz. 1844
SYNONYM(S): Sellaphora bacilliformis (Grunow) Mereschk. 1902 

Sellaphora japonica


Sellaphora meridionalis

LM scalebar = 10 µm = 80 pixels.


Contributor: David R.L. Burge | Mark Edlund - June 2017
Length Range: 32-53 µm
Width Range: 8.0-10.6 µm
Striae in 10 µm: 17-19


Valves are linear with slightly bowed margins. Apices are broadly rounded with small polar bars visible. Raphe branches are filiform, with a broad curve halfway between the center and end of the valve. Proximal raphe ends are inflated and unilaterally bent to the primary valve side. Terminal raphe fissures are initially deflected in a small question mark shape to the primary side, but then sharply curve to the secondary side on the mantle. The conopeum is small and located within a narrow, linear axial area that becomes expanded near the central area. The conopeum appears as narrow grooves running alongside the raphe and visible as faint lines under LM. The central area is laterally expanded and rectangular to weakly bow-tie shaped. The central area is bordered by 3-4 shortened stria of similar lengths. Striae are slightly curved and reflexed and are parallel at the valve center becoming slightly radiate at the apices. Areolae very fine, and not discernible in LM.

Sellaphora laevissima is part of a species group, or complex, that has not be adequately characterized (Mann et al. 2008).

The type material of Navicula laevissima contains many species of Sellaphora and it is uncertain as to which specimen corresponds to the holotype (Mann 1989). A lectotype was designated from Kützing material housed at the British Museum (Schoeman and Archibald 1976-1980, Lange-Bertalot et al. 2003).

Original Description

Basionym: Navicula laevissima
Author: Kütz. 1844
Length Range: µm
Striae in 10 µm:

Original Description

N. laevissima, vitrea, clara, bacilares, medio leviter ventricosa, apicibus late rotundas. Longit. 1/45”’. Fossil I’m Bergmehl von San Fiore.

Original Images

Cite This Page:
Burge, D., and Edlund, M. (2017). Sellaphora laevissima. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Sellaphora laevissima

Contributor: David R.L. Burge | Mark Edlund

Reviewer: Marina Potapova


Camburn, K.E. and Charles, D.F. (2000). Diatoms of Low-Alkalinity Lakes in the Northeastern United States. Academy of Natural Sciences of Philadelphia, Special Publication 18, 152 pp.

Camburn, K.E., Lowe, R.L., and Stoneburner, D.L. (1978). The haptobenthic diatom flora of Long Branch Creek, South Carolina. Nova Hedwigia 30: 149-279.

Cumming, B.F., Wilson, S.E., Hall, R.I. and Smol, J.P. (1995). Diatoms from British Columbia (Canada) Lakes and their relationship to salinity, nutrients and other limnological variables. Bibliotheca Diatomologica 31: 1-207.

Fallu, M.-A., Allaire, N. and Peinitz, R. (2000). Freshwater diatoms from northern Québec and Labrador (Canada). Species-environment relationships in lakes of boreal forest, forest-tundra and tundra regions. Bibliotheca Diatomologica 45: 1-200.

Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.

Lange-Bertalot, H., Cavacini, P., Tagliaventi, N. and Alfinito, S. (2003). Diatoms of Sardinia: Rare and 76 new species in rock pools and other ephemeral waters. Iconographia Diatomologica 12, 438 pp.

Mann, D.G. (1989). The diatom genus Sellaphora: Separation from Navicula. British Phycological Journal 24: 1-20.

Mann, D.G., Thomas, S.J. and Evans, K.M. (2008). Revision of the diatom genus Sellaphora: a first account of the larger species in the British Isles. Fottea 8(1): 15-78.

Mereschkowsky, C. (1902). On Sellaphora, a new genus of diatoms. Annals and Magazine of Natural History, series 7, 9: 185-195.

Pfitzer, E. (1871). Untersuchungen über Bau und Entwicklung der Bacillariaceen (Diatomaceen). Botanische Abhandlungen aus dem Gebiet der Morphologie und Physiologie. Herausg. von J. Hanstein, Bonn. 1(2): 189 pp.

Reavie, E.D. and Smol, J.P. (1998). Freshwater diatoms from the St. Lawrence River. Bibliotheca Diatomologica Band 41. J. Cramer, Berlin. 137 pp.

Schoeman, F.R. and Archibald, R.E.M. (1980). The diatom flora of Southern Africa. CSIR special report WAT 50. Pretoria.

Siver, P.A. and Hamilton, P.B. (2011). Diatoms of North America: The Freshwater Flora of Waterbodies on the Atlantic Coastal Plain. Iconographia Diatomologica 22.

Siver, P.A., Hamilton, P.B., Stachura-Suchoples, K. and Kociolek, J.P. (2005). Diatoms of North America. The Freshwater Flora of Cape Cod. Iconographia Diatomologica 14: 1-463.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Sellaphora laevissima CAS

NCBI Genbank Taxonomy

Sellaphora laevissima NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 170001

Autecology Discussion

Sellaphora laevissima is widely distributed in rivers of North America (Reavie and Smol 1998). It has been illustrated from lakes of New England (Camburn and Charles 2000), Quebec and Labrador (Fallu et al. 2000), mid-Atlantic states (Siver et al. 2005, Siver and Hamilton 2011) and British Columbia (Cumming et al. 1995). This taxon has been collected from lake sediments (Fallu et al. 2000) and growing in the epilithon of streams (Camburn et al. 1978). It has been reported from neutral to slightly acidic waters (Camburn and Charles 2000, Siver et al. 2005), lakes with an average dissolved organic carbon concentration of 6.54 mg/L (Fallu et al. 2000) and lakes with an average total phosphorus concentration from 9.6 to 18.8 µg/L (Camburn and Charles 2000, Siver and Hamilton 2011).


The distribution of Sellaphora laevissima in rivers of the continental United States, accessed on 29 June, 2017.

Credit/Source: USGS/Biodata

The distribution of Sellaphora laevissima in rivers of Alaska, accessed on 29 June, 2017.

Credit/Source: USGS/Biodata