Pinnularia nodosa var. percapitata

Krammer 2000      Category: Symmetrical biraphid
BASIONYM: Pinnularia nodosa var. percapitata Krammer 2000

Pinnularia nodosa

 

Pinnularia parvulissima

LM scalebar = 10 µm = 40 pixels.



Observations

Contributor: Loren Bahls - March 2014
Length Range: 43-70 µm
Width Range: 7.7-10.6 µm
Striae in 10 µm: 10

Description

Valves are linear with triundulate margins. In the largest specimens, the central undulation is wider than the distal undulations. Apices are distinctly capitate. Axial areas are about one-third the valve width and become wider from the apices towards the valve center. The central area is a bilateral fascia. The surface of the valve is mottled along either side of the raphe, continuing into the central area. The raphe is straight. Proximal raphe ends are bent to one side and terminate in small tear-shaped pores. Distal raphe fissures are shaped like question marks. Striae are weakly radiate at the valve center, becoming strongly convergent at the apices.



Original Description

Basionym: Pinnularia nodosa var. percapitata
Author: Krammer 2000
Length Range: 47-61 µm
Width Range: 9-10 µm
Striae in 10 µm: 8-10

Original Description

Original Images


Cite This Page:
Bahls, L. (2014). Pinnularia nodosa. In Diatoms of the United States. Retrieved April 27, 2017, from http://westerndiatoms.colorado.edu/taxa/species/pinnularia_nodosa_var._percapitata

Species: Pinnularia nodosa

Contributor: Loren Bahls

Reviewer: Sam Rushforth

Citations

Krammer, K. (2000). The genus Pinnularia. The Diatoms of Europe. Diatoms of Inland Waters and Comparable Habitats 1: 1-703.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Pinnularia nodosa var. percapitata CAS

North American Diatom Ecological Database (NADED)

NADED ID:

Autecology Discussion

The specimens of P. nodosa var. percapitata observed are from streams, ponds and small lakes in the northern Rocky Mountains of Montana. At these locations pH ranged from 6.10 to 7.78 and specific conductance ranged from 22 to 169 µS/cm. Water quality preferences of this variety appear to be similar to those of the nominate variety: low to moderate electrolyte content and low pH, most commonly found in peaty bogs and in springs (Krammer 2000).

Images

Indian Meadows Research Natural Area, Helena National Forest, Lewis & Clark County, Montana: home of Pinnularia nodosa var. percapitata.

Credit/Source: Loren Bahls