• Category
  • Length Range
    11.0-17.5 µm
  • Width Range
    5.0-6.0 µm
  • Striae in 10 µm
  • Reported As
    Planothidium rostratum (See UPDATES, below)



Valves are lanceolate to elliptic-lanceolate with rostrate to subcapitate apices. The raphe valve has a linear axial area and transversely rectangular central area. The rapheless valve has a linear-lanceolate axial area, which widens considerably in the valve center. The central area on the rapheless valve contains a cavum on the internal valve surface. The raphe is straight with expanded external proximal endings. Terminal raphe fissures are curved to the secondary side of the valve. The striae are multiseriate and radiate throughout both valves.

Original Description

  • Author
    C.E.Wetzel & Etor 2019
  • Length Range
    11.5-14.5 µm
  • Width
    5-6 µm
  • Striae in 10µm

Original Images

Plpotapovae Orig Ill
Plpotapovae Orig Descr


Mar 18, 2020 - Revision of Planothidium rostratum

From December 2010 to March 2020, this page appeared as Planothidium rostratum. Wetzel et al. (2019) proposed a more narrow concept of this taxon. This page was revised to reflect the recognition of Planothidium potapovae from P. rostratum sensu lato. - M. Potapova

Cite This Page

Potapova, M. (2010). Planothidium potapovae. In Diatoms of North America. Retrieved May 25, 2024, from https://diatoms.org/species/planothidium_potopovae


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