• Category
  • Length Range
    18.7-41.3 µm
  • Width Range
    5.5-6.7 µm
  • Striae in 10 µm
  • Synonyms
    Encyonema gracile Rabenh. 1853
  • Reported As
    Cymbella lunata (Patrick and Reimer 1975, p. 46, plate 7, figs. 11-14)
    Cymbella gracilis (Krammer and Lange-Bertalot 1986, p. 308, fig. 120: 3-5)



Valves are cymbelloid and narrow, with narrowly rounded apices. The dorsal margin is moderately arched. The ventral margin is weakly convex to nearly flat with a slightly tumid central valve. The central area is slightly wider than the axial area,. The raphe is lateral, narrowing near the proximal ends and terminal fissures. Proximal raphe ends are deflected dorsally and terminate in inconspicuous central pores. Distal raphe fissures are long and curved ventrally. Striae on the dorsal side are radiate and more widely separated at the valve center than near the apices. The median dorsal stria has a single isolated areola near the central area. The shorter striae on the ventral side are parallel to radiate near the valve center, becoming convergent near the apices. Areolae in the striae are fine and number 30-35 in 10 µm.


Encyonema neogracile is widespread and common in lakes, fens and mossy seeps in the mountains of the Northwest United States. These waters typically have low concentrations of nutrients, low to very low electrical conductance, and circumneutral pH.

Kootenai  Pond And  Citadel  Peaks
Credit: Loren Bahls
Kootenai Pond, Glacier National Park, Montana: home of Encyonema vulgare

Original Description

  • Author
    Krammer 1997
  • Length Range
    16-50 µm
  • Width
    5.5-6.6 µm
  • Striae in 10µm

Original Images

Encyonema neogracile orig illus 2
Encyonema Neogracile Origdesc

Cite This Page

Bahls, L. (2016). Encyonema neogracile. In Diatoms of North America. Retrieved July 15, 2024, from https://diatoms.org/species/encyonema_neogracile1


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Encyonema neogracile 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.