• Category
  • Length Range
    10.0-14.8 µm
  • Width Range
    3.3-4.4 µm
  • Striae in 10 µm
    35-39 in the center valve
  • Reported As
    Adlafia sp. 2 NAWQA EAM (NADED 204006)
    Navicula gysingensis (Foged 1952: 167, fig. 2 (7))



Valves are lanceolate, with capitate to rostrate ends. The axial area is narrow and the raphe is straight. Proximal raphe ends deflect slightly to one side, and distal ends deflect to the opposite side. Striae are radiate and are visible in LM around the central area. Striae are more dense toward the ends, where they may not be visible in LM.

Externally, the axial area is narrow. Internally, it is conspicuously raised. Striae are uniseriate, convergent at the apices and extend from the axial area over the valve face and onto a deep valve mantle. Internally, the helictoglossa is small and raised. Externally, the areolae are occluded by a sieve-like velum. Girdle bands are narrow and open. Girdle bands possess one row of areolae, except near the valve apices, where there are two rows of areolae.


Adlafia multnomahii has been verified in Oregon, California, Connecticut, New Hampshire, and Arkansas (Morales and Le 2005). In the type, and most abundant populations in Oregon and California, this taxon was found in circumneutral water (pH 7.1), specific conductivity 74-98.9 _S/cm, alkalinity 30 mg/L (as CaCO3), orthophosphate 0.02-0.05 mg/l, nitrite+nitrate 0.11-0.651 mg/l and temperature 20.7-20.9 °C.

Original Description

Valves lanceolate with capitate to rostrate apices (Figs. 1–26). Length 9–16 μm, width 4–5 μm, striae density (estimated from SEM) 37–45 per 10 μm. Raphe filiform with strongly unilaterally deflected (hooked) distal ends in an outer valve view and strongly unilaterally deflected proximal ends in an inner view (Figs. 27–35). Proximal and distal ends are deflected in opposite directions. Helictoglossa small and raised (Fig. 31). Axial area narrow in an outer view and conspicuously raised in an inner view (Figs. 27–32). Striae uniseriate, strongly radiate, convergent at apices, and running from the axial area onto a deep valve mantle (Figs. 27–30, 36). Striae continue at the valve apices, where they are only interrupted by the raphe distal hook (Figs. 27, 31). Areolae occluded by a sieve-like velum located on the outer side of the areolae Figs. 35, 37, 38). Girdle bands narrow, open, and bearing one row of areolae which becomes two toward the valve apices (Figs. 27–30, 33, 34, 37, 38). Plastids unknown. Etymology.—The species is named after the Multnomah tribe that flourished on the Willamette River’s Sauvie Island, a portion of which falls within the boundaries of the State of Oregon’s county named after the tribe.

  • Author
    E.Morales and Le 2005
  • Length Range
    9-16 µm
  • Width
    4-5 µm
  • Striae in 10µm

Original Images

Adlafia multnomahii orig illus
Adlafia multnomahii  SEM 1
Adlafia multnomahii  SEM 2
Adlafia multnomahii orig descr
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.

Cite This Page

LaLiberte, G. (2015). Adlafia multnomahii. In Diatoms of North America. Retrieved July 15, 2024, from https://diatoms.org/species/adlafia_multnomahii


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