Pinnularia borealis Ehr.
Length:27

 Width:7

 Striae:5






























Collection 1395

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Pinnularia borealis Ehr., Phys. Abh. Akad. Wiss. Berlin, for 1841:420, pl. 1(2), fig. 6; pl. 4 (1), fig. 5; pl. 4(5), fig. 4. 1843 (Patrick and Reimer 1966).

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Valve broadly linear with rounded ends. Axial area narrow. Median ends of the raphe turned slightly to one side; terminal fissures distinct. Central area rounded, transverse. Striae usually parallel; sometimes slightly radiate toward the center of the valve and slightly convergent near the ends. This species is distinguished by its slightly curved raphe and the shape of the axial and central areas. (Patrick and Reimer 1966).


  • Type Locality
    Uncertain, Chile(Patrick and Reimer 1966).

  • Synonyms
    Navicula borealis (Ehr.) Kutz., Bacill., p. 96, pl. 28, figs. 68, 72. 1844(Patrick and Reimer 1966).

  • Ecology
    Prefers cool water of low mineral content. Often found in river, but also in ponds. Has been found to be largely pH and Halobion indifferent(Patrick and Reimer 1966; Beaver 1981).

    Size ranges and morphology

  • Length is 28 to 110 micrometers (Patrick and Reimer 1966).
  • Width is 7 to 18 micrometers (Patrick and Reimer 1966).
  • Striae are 4 to 6 in 10 micrometers (Patrick and Reimer 1966).