Valves are elliptic. The raphe valve has a narrow linear axial area and a transversely rectangular central area. The raphe is filiform and straight with slightly expanded external distal and proximal ends. The internal proximal raphe ends are turned to opposite sides, while the internal distal ends have small helictoglossae. Striae are uniseriate and moderately radiate. The rapheless valve has a wide elliptic–lanceolate axial area and short triseriate striae.
Platessa kingstonii was described and documented from streams in north–central Pennsylvania. Conductivity in these streams ranged from 19 to 38 μ S cm−1, and pH was 6.0–6.5.
Platessa kingstonii occurs in high-quality California streams. This diatom was also noted in streams from Tennessee in a EPA National Rivers and Streams Assessment (NRSA 2018 BS2232, I. Ciugulea).
Potapova, M. (2012). Platessa kingstonii. In Diatoms of North America. Retrieved November 21, 2024, from https://diatoms.org/species/platessa_kingstonii
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Platessa kingstonii 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.