Fallacia vitrea

(Østrup) D.G.Mann in Round, R.M.Crawford and D.G.Mann 1990      Category: Symmetrical biraphid
BASIONYM: Frustulia vitrea Østrup 1901
SYNONYM(S): Navicula vitrea (Østrup) Hust. | Navicula festiva Krasske 

Fallacia subhamulata


Fragilaria amphicephaloides

LM scalebar = 10 µm = 80 pixels.


Contributor: Ian Bishop - January 2016
Length Range: 15-26 µm
Width Range: 5.1-6.6 µm
Striae in 10 µm: 26-30


Valves are lanceolate with rounded, protracted, rostrate ends. Striae are radiate throughout, measuring 26-30 in 10 µm. A large, lanceolate conopeum covers between 1/2 and 3/4 of the valve face. Longitudinal lines exist in the conopeum, near its margins. These lines, as determined by SEM, are valve-long breaks in the canopeum. This structure also has small, transverse striations on either side of the raphe. The axial area is narrow and the raphe is filiform, with relatively separated proximal ends. Distal raphe ends deflect unilaterally. Areolae not visible in LM.

Original Description

Basionym: Frustulia vitrea
Author: Østrup 1901
Length Range: 20-24 µm
Width Range: 5.5 µm
Striae in 10 µm:

Original Description

F. vitrea m. Fig. 30 660/1. L. 0,02-0,024 mm., B. 0,0055 mm. Valve nearly linear; apices truncate. Central pores comparatively distant. Striae exceedingly delicate, just visible on applying Zeiss’ Apochromate 2 mm.; they appear to be at right angles to the raphe. I think I have seen two longitudinal lines close to and parallel with the margin, but I am not quite sure of it. The reason why I have placed this small hyaline form under Frustulia is mostly on account of the appearance of its central nodule. It may perhaps be related to Navicula El Kab O.M. (Bacil. a. d. Natronthalern El Kab tab. XII, fig. 22) which the author places under the Navicula cuspidata group. Here and there. More conspicuous in a gathering labelled: »Covering bare spots on peaty ground«. South side of Trangisvaagfjord (Syderö)1.

Original Images

Cite This Page:
Bishop, I. (2016). Fallacia vitrea. In Diatoms of the United States. Retrieved April 26, 2018, from http://westerndiatoms.colorado.edu/taxa/species/fallacia_vitrea

Species: Fallacia vitrea

Contributor: Ian Bishop

Reviewer: Rex Lowe


Le Cohu, R. and Azémar, F. (2010). Les genres Adlafia, Kobayasiella, Fallacia, Microstatus et Naviculadicta (Bacillariophycées) recensés dans quelques lacs des Pyrénées françaises. Bulletin de la Société d'histoire naturelle de Toulouse 146: 5-13.

Østrup, E. (1901). Freshwater-Diatoms from the Faeröes. Botany of the Faeroes, part 1. Det. Nordiske Forlag. Copenhagen. pp. 260-290.

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Fallacia vitrea CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Fallacia vitrea

EMAP Response Plots

Fallacia vitrea

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.