Adlafia multnomahii

E.Morales and Le 2005      Category: Symmetrical biraphid

REPORTED AS: Adlafia sp. 2 NAWQA EAM (NADED 204006) | Navicula gysingensis (Foged 1952: 167, fig. 2 (7)) 

Actinocyclus normanii


Amphipleura pellucida

LM scalebar = 10 µm = 80 pixels.


Contributor: Gina LaLiberte - November 2015
Length Range: 10-15 µm
Width Range: 3.3-4.4 µm
Striae in 10 µm: 35-39 in the center valve


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.

Original Description

Author: E.Morales and Le 2005
Length Range: 9-16 µm
Width Range: 4-5 µm
Striae in 10 µm: 37-45

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.

Original Images

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 the United States. Retrieved April 21, 2018, from

Species: Adlafia multnomahii

Contributor: Gina LaLiberte

Reviewer: Marina Potapova


Morales, E.A. and Le, M. (2005). A new species of the diatom genus Adlafia (Bacillariophyceae) from the United States. Proceedings of the Academy of Natural Sciences of Philadelphia 154: 149-154.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Adlafia multnomahii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 204007

Autecology Discussion

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.