• Category
  • Length Range
    63-163 µm
  • Width Range
    20-33 µm
  • Striae in 10 µm
  • Reported As
    Navicula ludloviana (Patrick and Reimer 1966, p. 532, plate 51, fig. 2)
    Navicula ludloviana (Lange-Bertalot 2001, p. 46, fig. 63: 1)



Valves are lanceolate, with attenuated apices in larger specimens and blunt subrostrate apices in smaller specimens. The axial area widens gradually from the apices to a rhombic central area. The raphe is lateral. Proximal raphe ends are inflated and terminal raphe fissures are comma-shaped. Striae are strongly radiate throughout, somewhat curved and alternately long and short around the central area. Areolae number about 28 in 10 µm.


Extant populations of Navicula ludloviana have been recorded from Crater Lake, Diamond Lake, Upper Klamath Lake, Lake Creek and Snow Creek in Oregon, and from Lake Washington in Washington. Values for pH at these locations range from 7.1 to 9.5 and conductivity values range from 27 to 38 µS/cm. Navicula ludloviana has also been recorded from Neogene to Pleistocene fossil deposits in California, Oregon, and Washington (Bahls and Potapova 2015).

Snow  Creek  Or Orsnw1010 2191
Credit: Kirsten Gallo, Siuslaw National Forest
Snow Creek, Deschutes County, Oregon.

Original Description

  • Author
    A.Schmidt 1876

Original Images

Nav Ludloviana  Schmidt  Taf46 Fig15

Cite This Page

Bahls, L., Potapova, M. (2015). Navicula ludloviana. In Diatoms of North America. Retrieved July 19, 2024, from https://diatoms.org/species/navicula_ludloviana


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