• Reported As
    Encyonema prostratum (Diatoms of the US)



Valves are semi-lanceolate and dorsiventral. The dorsal margin of valve is highly arched. The ventral margin of the valve is slightly convex. Valve apices are broadly rounded and becoming rostrate in larger valves and usually ventrally bent. The narrow, straight axial area runs the length of the valve. The central area is circular. The raphe is simple. Proximal raphe ends curve slightly to the dorsal margin. Distal raphe ends deflect ventrally and do not reach the valve margin. Striae are punctate. Dorsal striae are radiate throughout, while ventral striae radiate at the valve center and become parallel, or even convergent, near the valve apices. Areola density 16-20 in 10 µm.

Note that Patrick and Reimer (1975) report the maximum length of this taxon (as Cymbella proxima) as 80 µm.

Examination of type material (Silva et al. 2013) led to determination that the name E. leibleinii has priority over E. prostratum (Berkeley) Kützing, which was previously used on this page (see UPDATE tab).


Colonies were found in a plankton tow of the wave zone in Silver Lake, Dickinson County, Iowa. Other specimens were found in episammon, epilithic, and dredge samples from West Lake Okoboji, Dickinson County, Iowa. The genus Encyonema is commonly colonial and grows in mucilage tubes that attach to substrate. They are found in many freshwater communities and are most common in lentic systems (Round et al., 1990).

12  Planktothrix And  Encyonema 1
Credit: Kalina Manoylov
Cells of growing within a mucilage tube, its typical growth habit. Cells of the blue-green alga Planktothrix surround the diatom colony.

Original Description

filis abbreviatis, granulis uniseriatis fuscis

  • Basionym
    Gloionema leibleinii
  • Author
    Agardh 1830

Original Images

Encyonema leibleinii LECTOTYPE


Mar 14, 2016 - Nomenclatural change

From 1 August 2014 to 14 March 2016, the specimens on this page were presented as Encyonema prostratum (Berkeley) Kützing 1844. Silva et al. (2013) examined the type material of a number of species of Encyonema and stated that E. prostratum, E. paradoxum and E. leibleinii are synonomous. The epithet of E. leibleinii, however, has priority and here becomes the name on this page. - S. Spaulding

Cite This Page

Alexson, E. (2014). Encyonema leibleinii. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/encyonema_leibleinii


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Encyonema leibleinii from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.