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Encyonopsis hustedtii

L.L.Bahls 2013      Category: Asymmetrical biraphid

Encyonopsis falaisensis


Encyonopsis krammeri

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - May 2013
Length Range: 14-20 µm
Width Range: 3.3-4.0 µm
Striae in 10 µm: 23-26


Valves are linear to linear-lanceolate with capitate apices. Valves are more or less symmetric along the apical axis. The axial area is narrow. The central area is rounded and variable in size. The raphe is filiform. Proximal raphe ends are weakly expanded and deflected dorsally. Distal raphe fissures are comma-shaped and curved to the ventral side. Striae are radiate throughout.

Original Description

Author: L.L.Bahls 2013
Length Range: 14.4-19.6 µm
Width Range: 3.3-4.0 µm
Striae in 10 µm: 23-26

Original Description

Valves linear to linear-lanceolate, not or scarcely dorsiventral. Apices capitate. Valve length 14.4–19.6 µm; valve width 3.3–4.0 µm. Axial area narrow. Central area rounded, variable in size. Raphe filiform, proximal ends unexpanded, deflected dorsally. Distal raphe fissures comma-shaped, curved to the ventral side. Striae weakly radiate throughout, 23–26 in 10 µm.

Original Images

Cite This Page:
Bahls, L. (2013). Encyonopsis hustedtii. In Diatoms of the United States. Retrieved May 22, 2018, from

Species: Encyonopsis hustedtii

Contributor: Loren Bahls

Reviewer: Mark Edlund


Bahls, L. (2013). Encyonopsis from western North America: 31 species from Alberta, Idaho, Montana, Oregon, South Dakota, and Washington, including 17 species described as new. Northwest Diatoms, Volume 5. The Montana Diatom Collection, Helena, 46 pp.

Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema part., Encyonopsis and Cymbellopsis. Bibliotheca Diatomologica 37:1-469.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)


Autecology Discussion

Encyonopsis hustedtii is widespread and locally common in small streams, springs, and mossy seeps in the Northern Rockies. These waters have somewhat alkaline pH (pH 7.3-8.0) and low to moderate concentrations of dissolved solids (255-411 µS/cm).


Blakiston Beaver Pond A, Waterton Lakes National Park, Alberta: type locality of Encyonopsis hustedtii.

Credit/Source: Barb Johnston, Parks Canada