• Category
  • Length Range
    8-17 µm
  • Width Range
    4.5-6.0 µm
  • Striae in 10 µm
    25–29 on raphe valve, 12–15 on rapheless valve



Valves are elliptic. The raphe valve has a narrow linear axial area and a wide, bow-tie-shaped central area. The raphe is straight, filiform, without terminal fissures, and with external distal ends slightly expanded into drop-like pores. The external proximal raphe ends are straight, and positioned within a shallow groove. There are helictoglossae at the internal distal raphe ends. The striae on the raphe valve are uniseriate, and strongly radiate. The rapheless valve has a wide lanceolate axial area bordered by short and broad biseriate striae. The internal openings of areolae on both valves are round.


Platessa lutheri has been reported from oligotrophic circumneutral waters and aerial habitats of Europe and North America (Krammer & Lange-Bertalot 2004). This species is rare in the US: it was found by Johasen et al. (2004) in the Great Smoky Mountain National Park and there is one record in the ANSP databases from the Murderkill River, Delaware.

Original Description

  • Basionym
    Achnanthes lutheri
  • Author
    Hust. 1933
  • Length Range
    9 µm
  • Width
    4.5 µm
  • Striae in 10µm
    30 on raphe valve, 15–16 on rapheless valve

Original Images

Achnanthes lutheri orig illus
Achnanthes lutheri orig descr

Cite This Page

Potapova, M. (2012). Platessa lutheri. In Diatoms of North America. Retrieved April 21, 2024, from https://diatoms.org/species/platessa_lutheri


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