• Category
  • Length Range
    52-105 µm
  • Width Range
    8.8-11.2 µm
  • Striae in 10 µm



The valves are narrow and lanceolate, with acutely rounded ends. The axial area is narrow and linear. The central area is rhombic. The raphe is straight with proximal ends that are hooked to the secondary side. The transapical striae are strongly radiate, bent in the valve center and convergent near the poles. Lineolae number 28-32 in 10 μm.

Note that this concept of N. radiosa is similar to that of Lange-Bertalot (2001) and includes considerable morphological variation, especially in the overall shape of the valve and in the shape of the apices. Further investigations may reveal pseudocryptic species within N. radiosa.


This taxon is common in rivers and lakes of the US. It is considered a tolerant species and is found in waters of high conductance and nutrient concentrations. It is able to live in rivers with embedded benthic substrates, in turbid waters, and tolerates human disturbance.

Original Description

  1. NAVICULA RADIOSA. Taf. 4. Fig. XXIIl, (420/1). N. mediocris lanceolata, gracilίs, acuta, striis radiantibus distinctis, in 1/100’’’15-18. Long.1/30‘‘‘ In Süsswassergräben bei Halle! Weissenfels ! Nordhausen! — Die Streifen sind stärker und deutlicher als bei N. gracilis, der sie übrigens sehr ähnlich ist.
  • Author
    Kütz. 1844
  • Length Range
    75 µm
  • Striae in 10µm

Original Images

Navicula Radiosa  Ill
Navicula Radiosa  Descr

Cite This Page

Potapova, M. (2011). Navicula radiosa. In Diatoms of North America. Retrieved April 14, 2024, from https://diatoms.org/species/navicula_radiosa


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