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Eunotia sarraceniae

E.E.Gaiser and J.R.Johans. 2000      Category: Eunotioid

Eunotia rushforthii


Eunotia serra

LM scalebar = 10 µm = 40 pixels.


Contributor: Mark Edlund | David R.L. Burge - June 2017
Length Range: 21-66 µm
Width Range: 3.9-5.9 µm
Striae in 10 µm: 18.5-22.5


Frustules lanceolate in girdle view because of amphoroid symmetry. Valves strongly arcuate with convex dorsal and concave ventral margins; dorsal margin more arched. Ends acutely rounded. Small but distinct helictoglossae located subterminally along ventral margin. Two rimoportulae per valve, located at each valve end. Striae parallel, slightly finer density at valve ends.

Although Gaiser and Johansen (2000) reported this taxon to have rectangular frustules in girdle view, we found several specimens on the type slide that are lanceolate in girdle view because valves have broader dorsal mantles than ventral mantles. We also clearly illustrate that there are two rimoportulae per valve, one at each end (Edlund and Brant 2010), a feature that was not reported in the original description.

Original Description

Author: E.E.Gaiser and J.R.Johans. 2000
Length Range: 30.5-52 µm
Width Range: 4-6 µm
Striae in 10 µm: 22-28

Original Description

Frustules rectangular in girdle view. Valve lunate or arcuate, with strongly convex dorsal margin and smoothly concave ventral margin, 4.0-6.0 µm wide (mean = 4.8 µm), 30.5-52 µm long (mean = 35.1 µm). Apices of valve acute or rounded, narrowing to slightly attenuated at ends. Short terminal nodules (helictoglossae) distinct on ventral margin, somewhat removed from apices of the valve. Striae parallel, fine, 22-28 in 10 µm (mean = 24).

Original Images

Cite This Page:
Edlund, M., and Burge, D. (2017). Eunotia sarraceniae. In Diatoms of the United States. Retrieved May 25, 2018, from

Species: Eunotia sarraceniae

Contributor: Mark Edlund | David R.L. Burge

Reviewer: Evelyn Gaiser


Edlund, M.B. and Brant, L.A. (2010). Eunotia charliereimeri, a new Eunotia species (Bacillariophyceae) with amphoroid frustule symmetry. Proceedings of the Academy of Natural Sciences of Philadelphia 160(1):47-56. 10.1635/053.160.0106

Gaiser, E.E. and Johansen, J. (2000). Freshwater diatoms from Carolina bays and other isolated wetlands on the Atlantic Coastal Plain of South Carolina, USA, with descriptions of seven taxa new to science. Diatom Research 15(1): 75-130. 10.1080/0269249X.2000.9705487

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Eunotia sarraceniae CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Eunotia sarraceniae is currently known only from the “Carolina bays” area near its type locality, Sarracenia Bay in western South Carolina. Gaiser and Johansen (2000) found it rare to uncommon in 17 bays, where this taxon was found on mosses, as epiphyton, in leaf litter, and in the plankton. It had an optimum pH of 4.5 and water depth of 13 cm. Common associates were Eunotia and Pinnularia spp.