Encyonema minutum var. pseudogracilis

(Cholnoky) Czarn. 1994      Category: Asymmetrical biraphid
BASIONYM: Cymbella turgida var. pseudogracilis Cholnoky 1958
SYNONYM(S): Cymbella minuta var. pseudogracilis (Cholnoky) Reimer 1975 | Encyonema neomesianum Krammer 1997 

Encyonema lunatum


Encyonema neogracile

LM scalebar = 10 µm = 40 pixels.


Contributor: Ian Bishop - March 2017
Length Range: 42-60 µm
Width Range: 12.3-13.0 µm
Striae in 10 µm: 7-9 at mid-valve; up to 11 at the dorsal apex and 13 at the ventral apex


Valves are dorsiventral, with a broadly rounded dorsal margin and a linear ventral margin that expands at the center. Valve apices are rounded to slightly apiculate. Dorsal striae are radiate throughout, and ventral striae are radiate to convergent. Dorsal striae are regularly spaced, while ventral striae vary in density and length across the apical axis. Areolae are coarse and easily visible in LM, measuring 21-24 in 10 µm. A single stigmoid occurs in line with the central dorsal stria. The axial area is narrow near the apices, and gradually widens toward mid-valve. Terminal nodules are clearly visible. The raphe is for the most part lateral, becoming filiform at ends, and its proximal ends are unilaterally deflected toward the dorsal margin.

Original Description

Basionym: Cymbella turgida var. pseudogracilis
Author: Cholnoky 1958
Length Range: 40-50 µm
Width Range: 9-10 µm
Striae in 10 µm: 9-11 (mid-dorsal)

Original Description

Original Images

Cite This Page:
Bishop, I. (2017). Encyonema minutum. In Diatoms of the United States. Retrieved April 22, 2018, from http://westerndiatoms.colorado.edu/taxa/species/encyonema_minutum_var._pseudogracilis

Species: Encyonema minutum

Contributor: Ian Bishop

Reviewer: Marina Potapova


Cholnoky, B.J. (1958). Beiträge zur Kenntnis der Südafrikanischen Diatomeenflora. II. Einige Gewässer im Waterberg-Gabiet, Transvaal. Portugaliae Acta Biologica, Séries B 6 (2): 99-160.

Czarnecki, D.B. (1994). The Freshwater Diatom Culture Collection at Loras College, Dubuque, Iowa. Kociolek, J.P. (ed.) Proceedings of the 11th International Diatom Symposium, California Academy of Sciences, San Francisco, CA, p. 155-173.

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

Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 1. Allgemeines und Encyonema. Bibliotheca Diatomologica 36: 1-382.

Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Encyonema minutum var. pseudogracilis CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Encyonema minutum var. pseudogracilis has been reported across three continents (Africa, South America, and North America). The species was described from South Africa (Cholnoky 1958) and noted its occurence in weakly acidic freshwater habitats. It has been reported across the eastern United States (Patrick and Reimer 1975). The populations examined for this taxon page were collected in the southeast, from Georgia to North Carolina.