Valves are elliptical to linear-elliptical. The raphe valve has a linear axial area and a small asymmetric central area. The raphe is straight, without terminal fissures. The central raphe ends curve toward opposite sides internally. The rapheless valve has a rhomboid axial area, which often has an irregular border. The central area on rapheless valve is usually not differentiated from the axial area. Striae are slightly radiate in the center and strongly radiate at the apices of both valves, 24-30 in 10 µm. One row of areolae is present on the mantle of both valves. Areolae are often visible in LM.
Schalen elliptisch mit breit gerundeten Enden, 6-9 μ lang, 4-5 μ breit. Raphenlose Schalen mit breit lanzettlicher bis elliptischer Axialarea, Transapicalstreifen kurz, radial, 21-23 in 10 μ. Raphenschale mit feiner, fadenförmiger Raphe, Axialarea sehr eng, Zentralarea klein, rundlich bos etwas quer verbreiert, Transapikalstreifen 22-28 in 10 μ, von der Mitte gegen die Enden allmählich enger werdend, leicht radial, sehr zart punktiert.
Potapova, M. (2010). Psammothidium levanderi. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/44748/psammothidium_levanderi
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Psammothidium levanderi 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.
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