• Category
  • Length Range
    29.4-78.2 µm
  • Width Range
    10.5-14.3 µm
  • Striae in 10 µm
    8-12 at the valve center, up to 14 near the apices



Valves are lanceolate and dorsiventral, with bluntly rounded apices. The dorsal margin is moderately arched. The ventral margin is nearly flat, with a slightly gibbous center. The axial area is narrow, barely wider than the raphe, and located just ventral to the valve mid line. The central area is small and rhombic in shape. The raphe is distinctly lateral, becoming reverse lateral at the proximal ends. Proximal raphe ends are deflected ventrally and terminate in small pores. Distal raphe fissures are filiform and deflected dorsally at about 45 degrees. Striae are radiate throughout, and more strongly radiate near the apices. Areolae are distinct in LM and number 18-24 in 10 µm. Isolated stigmata number 2-5 at the proximal ends of the median ventral striae.


Cymbella maggiana has been collected from two streams in adjacent watersheds of Glacier National Park, Montana. These streams--Logging Creek and Quartz Creek--are on the west side of the Park in the Flathead River drainage. At the time of collection, pH and specific conductance measured 7.74 and 50 µS/cm, respectively, in one of these streams (Logging Creek). The type locality of this species is the River Maggia in Ticino, Switzerland. Krammer (2002) reports that this species is found in several oligotrophic alpine rivers in this region of the Alps.

Original Description

  • Author
    Krammer 2002
  • Length Range
    43-63 µm
  • Width
    10.5-12.7 µm
  • Striae in 10µm
    10-12 at the valve center, up to 15 near the apices

Original Images

Cymbella maggiana orig desc
Cymbella maggiana orig illus
Cymbella maggiana orig descr

Cite This Page

Bahls, L. (2016). Cymbella maggiana. In Diatoms of North America. Retrieved May 24, 2024, from https://diatoms.org/species/cymbella_maggiana


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