Ulnaria

Ulnaria is a genus of long, thin diatoms that often have a narrower central area where "ghost striae" may be present. Ulnaria attach to the bottom of lakes and are not free floating, despite not possessing a raphe system or being motile.

U. contracta

Cells are 65 - 149 µm in length, 6.5 - 6.8 µm in width.
Rows of striae are 10 - 12 per 10 µm.
Striae are usually parallel and opposite each other, but towards the tips they begin to curve and alternate.

For more information, visit diatoms.org here.

A8m1 Ulnaria contracta (_)_edited

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Unidentified Ulnaria sp.

Other identification sources have been sparce on help identifying these Ulnaria, but it seemed important to include them in the catalogue of Mendota species.
Samples range from 96 - 140 µm in length
May actually be 2 different species: see contraction and dilation at the center of the third image.

A3m3 Ulnaria sp

A1m1 Ulnaria sp

A1m1 Ulnaria sp 1

Mendota Diatoms

A local field guide to Wisconsin algae

Ulnaria

U. contracta

Cells are 65 - 149 µm in length, 6.5 - 6.8 µm in width.

Rows of striae are 10 - 12 per 10 µm.

Striae are usually parallel and opposite each other, but towards the tips they begin to curve and alternate.

For more information, visit diatoms.org here.

Unidentified Ulnaria sp.

Other identification sources have been sparce on help identifying these Ulnaria, but it seemed important to include them in the catalogue of Mendota species.

Samples range from 96 - 140 µm in length

May actually be 2 different species: see contraction and dilation at the center of the third image.