• Synonyms
    Gomphonema acuminatum var. elongatum (W.Sm.) Carruth. 1864



Valves acuminate-apiculate. The apex is protracted and blunt with a weakly expanded headpole. The central portion of the valve is tumid. The axial area is straight and wider at the apices than at the central valve. The central area is transversely widened, formed by two (one on each side) shortened central striae, and on one side is positioned a single isolated stigma. The punctate striae are radiate about the center, becoming parallel towards the ends, then becoming radiate at the headpole and footpole. The striae at the central valve are more widely spaced than the rest of the striae.


Original Description

  • Author
    W.Sm. 1855

EMAP Assessment

EMAP Distribution

Gomphonema Acuminatum Var  Elongatum  Smith 40
Map 40

Response Plots

Gomphonema Acuminatum Var  Elongatum  Smith

Cite This Page

Kociolek, P. (2011). Gomphonema elongatum . In Diatoms of North America. Retrieved June 19, 2018, from https://diatoms.org/species/gomphonema_elongatum


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