• Category
  • Length Range
    7-24 µm
  • Width Range
    4.5-8.0 µm
  • Striae in 10 µm
  • Synonyms
    Achnanthes lanceolata (Bréb. ex Kütz.) Grunow in Van Heurck



Valves are lanceolate to elliptical-lanceolate with slightly drawn-out apices. The raphe valve has a linear axial area and central area that varies in shape - from transversely rectangular to elliptical. The rapheless valve has a linear-lanceolate axial area that slightly widens in the middle. The asymmetrical central area on the rapheless valve contains a rimmed depression on the internal valve surface.The raphe is straight with expanded external proximal endings. Terminal raphe fissures are curved to the secondary valve side. The striae are multiseriate and radiate throughout both valves.

Original Description

A. a latere secundario elliptico – lanceolato; apicibus obtusis, rotundatis. — Long. 1/140'''.

  • Basionym
    Achnanthidium lanceolatum
  • Author
    Bréb. ex Kütz. 1846
  • Length Range
    16 µm

Original Images

Orig Descr Pllanc

Cite This Page

Potapova, M. (2010). Planothidium lanceolatum. In Diatoms of North America. Retrieved May 18, 2024, from https://diatoms.org/species/planothidium_lanceolatum


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