• Category
  • Length Range
    12-20 µm
  • Width Range
    3-4.5 µm
  • Striae in 10 µm
    Difficult to resolve in LM



Valves are semi-lanceolate, with a smoothly arched dorsal margin, and straight to slightly convex ventral margin. Valve ends are protracted, narrowly rostrate and ventrally curved. The raphe is located near the middle of the valve, gently arched with proximal raphe ends slightly deflected dorsally. The axial area is narrow, although somewhat difficult to resolve on the ventral side. The central area on the dorsal side forms a thickened semi-stauros extending to the dorsal valve margin, a ventral fascia is present and extends to the ventral valve margin. Dorsal and ventral striae are difficult to resolved in LM.

Original Description

  • Basionym
    Amphora montana
  • Author
    Krasske 1932
  • Length Range
    9-15 µm
  • Width
    4-6 µm
  • Striae in 10µm

Original Images

Krasske 1932 Plate
Krasske 1932 Text

Cite This Page

Stepanek, J., Kociolek, P. (2011). Halamphora montana. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/halamphora_montana


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