Polynomial visual identification key is a tool created to help you identify species. With PVIK you will fast narrow down the number possible species. Species are devided in groups on genus level. Choose your group, enter the size and you will see the relevant species on a table. You can then further narrow down possibilities by choosing other features. PVIK may not always offer only one result, but it saves your time when you can concentrate on only few possible species. At the same time PVIK gives a great opportunity to learn and compare different species.

Closterium parallel

Closterium - almost straight, only curved in the ends, midregion parallel, width < 25µm, no girdles

010020030040050060070080090001020304050width (µm)length (µm)C. aciculareC. delponteiC. gracileC. gracileC. gracileC. gracileC. limneticumC. limneticumC. limneticumC. lineatumC. lineatumC. nordstedtiiC. nordstedtiiC. praelongumC. praelongumC. strigosumC. strigosumC. subscotiumC. toxon

Filters

Candidates

Closterium delpontei Wolle 1885

Note : Ventral margin can be slightly convex. Striation coarse, space between the striae punctate.

Closterium lineatum var. lineatum Ehrenberg ex Ralfs 1848

Note : Very rarely false girdle bands.

Closterium praelongum var. brevius (Nordstedt) Willi Krieger 1935

Note : Usually not excatly paralle midregion, a slight inflation on the ventral side.

Closterium praelongum var. praelongum Br‚bisson 1856

Note : Not seldom with one or two false girdle bands. Can have delicate punctae or short striae in logitudal series.

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