Pinnularia biceps f. petersenii Ross
Length:29

 Width:6.5

 Striae:14






























Collection 1404

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Authority information

Pinnularia biceps f. petersenii Ross, Natl. Mus. Canada Bull., No. 97, pt. 2, p. 201; pl. 9, fig. 11? 1947(Patrick and Reimer 1966).

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This image was taken with an additional 40% magnification.



This image was taken with the additional magnification and utilizing DIC.


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Valve linear with rostrate to subcapitate apices. Axial area distinct, widening toward teh central area which is a transverse fascia. Striae radiate a the center of the valve, convergent toward the apices. This form is distinguished from the nominate variety by its smaller size and its larger central area in proportion to the length of the valve (Patrick and Reimer 1966).


  • Type Locality
    Near hot spring, Iceland on ground in front of house (Hlad) Modrn vellir (Kjos) 6/8(Patrick and Reimer 1966).


  • Synonyms
    Pinnularia interrupta f. minor Peters. in Bot. Iceland, vol. 2, pt. 2, p. 405, fig. 25. 1928(Patrick and Reimer 1966).


  • Ecology
    Widely distributed in circumneutral water(Patrick and Reimer 1966).

    Size ranges and morphology

  • Length is 22 to 30 micrometers (Patrick and Reimer 1966).
  • Width is 4.5 to 6 micrometers (Patrick and Reimer 1966).
  • Striae are 12 to 14 in 10 micrometers (Patrick and Reimer 1966).