• Category
  • Length Range
    73-139 µm
  • Width Range
    9-18 µm
  • Striae in 10 µm
    16 in the center, 20 at the ends
  • Synonyms
    Stauroneis nobilis var. baconiana (Stodder) Reimer



Valves are linear-lanceolate, narrowing very gradually to long, protracted, rostrate apices. The raphe is lateral, becoming filiform and straight at the proximal ends. The proximal raphe ends are not expanded. The axial area is narrow and linear, expanding slightly near the central area. The stauros is narrow and rectangular. Occasionally short striae are present in the stauros. Striae along the border of the stauros are parallel, becoming radiate to more steeply radiate near the valve apices. Areolae are round to transversely oblong. Areolae are irregularly spaced near the central area and become more closely spaced toward the apices, 14-18 in 10 µm.

Although Reimer (1961) treated this taxon as a variety (S. nobilis var. baconiana), it is recognized here at the species level, as originally described (Stodder, 1859).


In the Northern Rockies, Stauroneis baconiana has been found in Fish Lake and Three Bears Lake in Glacier National Park and in a few ponds and small lakes in western Montana. These are all small, shallow bodies of water with abundant submerged and emergent vegetation. In these waters pH ranges from 6.1 to 8.6 and specific conductance ranges from 22 to 192 µS/cm. This taxon has also been reported from a stream and ponds in Massachusetts (Reimer 1961, Siver et al. 2005) and from Grass Pond in the Adirondak Mountains of New York State (Camburn & Charles 2000).

Bloody  Dick  Pond 7 1
Credit: Loren Bahls
Bloody Dick Pond #7, Beaverhead County, Montana: home of Stauroneis baconiana.

Original Description

  • Author
    Stodder 1859

Original Images

Stauroneis Baconiana  Orig Descr

Cite This Page

Bahls, L. (2011). Stauroneis baconiana. In Diatoms of North America. Retrieved June 17, 2018, from https://diatoms.org/species/stauroneis_baconiana


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