• Category
  • Length Range
    42.5-48.5 µm
  • Width Range
    8.0-9.0 µm
  • Striae in 10 µm
    30-32 in the center valve, 34-35 at the ends



Valves are linear-lanceolate, with very slightly constricted apices. Populations often exhibit a narrow size range. Areolae are round or oval. They form transverse striae that are radiate at the center of the valve and slightly or strongly convergent near the apices. Striae circumradiate the apices. The single row of areolae closest to either side of the raphe forms a continuous line that begins and ends at the poles and curves around the rounded central area. This feature is distinct under the light microscope, especially at the central area. Small, irregularly spaced poroids are present in the central area or near the raphe. The raphe branches and longitudinal ribs are slightly curved. The longitudinal ribs fuse with the helictoglossae to form a porte-crayon. These longitudinal ribs are incomplete at the central nodule. The central nodule is relatively flat. The external proximal and distal raphe ends form a small Y-shape, a feature observable with electron microscopy. The shape of the central area is generally ovoid, and the size of the central area may vary within a population.

These records of Frustulia asiatica are from Hawaii. To date, this species has not been documented from the continental US, however F. asiatica can be compared to populations in California. We have observed California specimens that are similar in morphology to both F. asiatica and F. vulgaris. Further work may be needed to determine if the California specimens are a separate species.


Original Description

FRUSTULIA VULGARIS Thwaites var. ASIATICA var. nov. Plate 2, fig. 12.

Valve lanceolate, with obtuse rounded ends. Length, 0.0527 millimeter; breadth, 0.0102. Striae, 23 in 0.01 millimeter.

  • Basionym
    Frustulia vulgaris var. asiatica
  • Author
    Skvortzow 1928
  • Length Range
    53 µm
  • Width
    8.5 µm
  • Striae in 10µm

Original Images

Frustulia vulgaris var. asiatica orig illus
F Vulgaris Asiatica Orig Des

Cite This Page

Graeff, C. (2012). Frustulia asiatica. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/frustulia_asiatica


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