• Category
  • Length Range
    76-123 µm
  • Width Range
    15-19 µm
  • Striae in 10 µm



Valves are linear, with nearly parallel sides. The apices are cuneate, slightly wider than the rest of the valve. The axial area is linear, approximately 1/3 of the valve width. The central area is rhombic or rounded with a transverse fascia, often with variously shaped markings. The thick sternum can be seen in LM as it runs across the central area. The raphe is lateral with proximal sections gently inclined towards the primary side and terminating with pores that are bent toward the secondary side. Terminal raphe fissures are shaped like question marks. Striae are slightly radiate near the valve center, becoming slightly convergent near the apices.


Pinnularia cardinaliculus was described from Massachusetts and is frequent in sediments of lakes in eastern North America. According to Krammer (2000), it is common in fossil deposits in eastern US (of uncertain age and location). J. Lund and F. Round observed P. cardinaliculus and the mode of its colony formation in English Lake District (Round 1988).

Original Description

  • Author
    Cleve 1895
  • Length Range
    80-100 µm
  • Width
    15-18 µm
  • Striae in 10µm

Original Images

Pinn Cradinaliculus Orig Ill
Pinn Cradinaliculus Orig Descr

Cite This Page

Friedman, N., Potapova, M. (2021). Pinnularia cardinaliculus. In Diatoms of North America. Retrieved June 20, 2024, from https://diatoms.org/species/pinnularia-cardinaliculus


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