Valves are lanceolate-clavate, broadest at the center with a broadly-rounded headpole and rounded footpole. The axial area is narrowly lanceolate, forming a distinct, mostly irregular elliptical central area. A single stigma is present. The central area is formed by 4-5 shortened striae on either side. The raphe is weakly undulate and lateral. Striae are punctate, uniseriate, and radiate (becoming parallel in some specimens). The apical pore field is distinct and bi-lobed. Septa are frequently observed.


Original Description

Gomphonema ventricosum, W. G. -- This well-marked species occurs in a gather from the banks of the Spey, near Elchies, different from that which I have spoken of as the Elchiies gathering. The middle part of is much expanded, and both extremities are obtuse and rounded, the longer limb being a little expanded at the apex. It is short and broad in proportion, and very uniform in its characters. Length about 0014 inch. Striae about 30 or 32 in 001". Dr. Greville has recently (April, 1855) found this species tolerably frequent in several gatherings made by him near the Bridge of Allan.

  • Author
    W.Greg. 1856
  • Striae in 10µm

Original Images

Cymbella ventricosum orig desc
Gomphonema ventricosum orig descr

EMAP Assessment

EMAP Distribution

Gomphonema Ventricosum 40 Copy
Map 40

Response Plots

Gomphonema Ventricosum Copy

Cite This Page

Kociolek, P. (2011). Gomphonema ventricosum. In Diatoms of North America. Retrieved June 24, 2018, from


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