Diatoms of North AmericaDiatoms of North America
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Compare Ulnaria acus

(Kütz.) Aboal 2003

Compare

Ulnaria ulna differs by wider (6.3-7.7 µm), needle shaped (parallel sides) valves. Ulnaria delicatissima valves have needle shaped valves with short, constricted apices. Fragilaria grunowii has more narrow valves (2-4 µm) and more attenuated, narrow apices. Both Fragilaria crotonensis and Fragilaria tenera are smaller in size. Fragilaria crotonensis often has an inflated central area, has a higher stria density, strongly narrowing apices and forms long, ribbon-like colonies. Fragilaria tenera forms stellate colonies.

LM scalebar = 10 µm
Ulnaria delicatissima LM14 Ulnaria delicatissima LM8 Ulnaria delicatissima LM7 Ulnaria sp. IT ILL 2015 LM1 Ulnaria delicatissima LM5 Ulnaria acus LM7 Ulnaria acus LM10
Length Range
60.5-251.6 µm
Width Range
4.2-4.9 µm
Striae in 10 µm
11-12

Ulnaria delicatissima

(W.Sm.) Aboal and Silva 2004

Ulnaria delicatissima LM15 Ulnaria delicatissima LM16 Ulnaria delicatissima LM18 Ulnaria delicatissima LM19 Ulnaria delicatissima LM20 Ulnaria delicatissima LM21 Ulnaria delicatissima LM22
Length Range
158.2-262 µm
Width Range
5 µm
Striae in 10 µm
10-11

Fragilaria crotonensis

Kitton 1869

Ansp Gc112455 5 Ansp Gc112455 6 Ansp Gc112455 1 Ansp Gc112455 11 Ansp Gc112455 3
Length Range
60-72 µm
Width Range
2-3 µm
Striae in 10 µm
17-18

Fragilaria tenera

(W.Sm.) Lange-Bert. 1980

F Tenera 114970 3 10 Um Bar F Tenera 114970 6 10 Um Bar F Tenera 114970 9 10 Um Bar F Tenera 114970 5 10 Um Bar F Tenera 114970 8 10 Um Bar F Tenera 114970 7 10 Um Bar F Tenera 114970 4 10 Um Bar
Length Range
50-75 µm
Width Range
2.0-2.5 µm
Striae in 10 µm
15-17

Also compare to

Ulnaria ulna

(Nitzsch) Compère

Fragilaria grunowii

Lange-Bert.