• Category
  • Length Range
    10-16 µm
  • Width Range
    3-4 µm
  • Striae in 10 µm



Valves are asymmetrical to the apical axis, the dorsal margin is distinctly convex, then ventral margin is slightly convex. The apices are protracted and relatively large compared to the size of the valve, broadly rounded, and curved slightly towards the dorsal margin. The axial area is narrow. The central area is indistinct, when present it is formed by a short stria on the ventral margin. The raphe is filiform and slightly arched towards the dorsal margin. Striae are parallel on the dorsal margin, radiate on the ventral margin.

Original Description

C. microcephala Grun. (Atl. Ρ1. VΙΙΙ fig. 36-39 — in Type Νο 211.) Valves assez étroitement lanceolées, à peine cymbiformes, à extrémités fortement rostrées-capitées ; raphé faiblement arqué ; stries délicates, 24 dans les grandes formes, 28 à 30 dans les petites formes. Longueur : 1 1/2 à 2 1/3 c.d.m.

  • Basionym
    Cymbella microcephala
  • Author
    Grunow 0

Original Images

Encyonopsis Microcephala  Ill
Encyonopsis Microcephala  Descr

Citations & Links

Cite This Page

Kociolek, P. (2011). Encyonopsis microcephala. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/encyonopsis_microcephala


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