• Category
  • Length Range
    5.9-13.0 µm
  • Width Range
    3.2-4.9 µm
  • Striae in 10 µm
    22-26 on raphevalve, 18-20 on rapheless valve



Valves are linear-elliptical with capitate to rostrate apices. Both raphe and rapheless valves have a lanceolate axial area and no distinct central area. The raphe is straight. Striae on raphe valve are radiate, becoming parallel to slightly convergent toward the apices, interrupted by a thin longitudinal line in the middle of the valve, 22-26 in 10 µm. Each stria in the middle of the raphe valve consists of two transapically elongated areolae. Striae near apices consist of a single areola. The striae on rapheless valve are slightly radiate, becoming parallel to slightly convergent toward the apices, interrupted by a wide longitudinal hyaline area on each side of the valve, 18-20 in 10 µm. Each stria consists of two transapically elongated areolae that also form longitudinal rows.


Original Description

Valvae lineari-ellipticae apicibus late capitatis, circiter 10 µ longae, 4 µ latae. Rhaphovalva rhaphi directa, area axiali angustissima, area centrali nulla, striis ad rhaphin perpendicularibus, circiter 24 in 10 µ. Areovalva area axialis anguste lanceolata, striis transapicalibus validis, circiter 20 in 10 µ, ad rhaphin fere perpendicularibus, utrimque una costa longitudinali decussatis.

  • Basionym
    Achnanthes amoena
  • Author
    Hust. 1952
  • Length Range
    10 µm
  • Width
    4 µm
  • Striae in 10µm
    24 on raphe valve, 20 on rapheless valve

Original Images

Karamoena  Orig Ill
Karamoena  Orig Descr

EMAP Assessment

EMAP Distribution

Karayevia Amoena 40 Copy
Map 40

Response Plots

Karayevia Amoena Copy

Cite This Page

Potapova, M. (2010). Karayevia amoena. In Diatoms of North America. Retrieved June 20, 2018, from https://diatoms.org/species/karayevia_amoena


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