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Desmids have the ability to move slowly on the surface excreting mucilage out of special pores. The picture shows this pores of Euastrum oblongum. High resolution DOF picture assembled of over 40 shots (manually stacked) taken with Planapo 63/1.4 showing the multilevel surface structur. See zip archive for details. Sample from sphagnum pond situated in the northern alpine region of Austria near Salzburg. Images were taken using Zeiss Universal with Olympus C7070 CCD camera.
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Euastrum oblongum (GREV.) RALFS ex RALFS The cells are appr. 2 times longer than wide and slenderly elliptical in shape. The cell halves consists of two clearly distinguishable sets of lobes which are weakly concave in the center. The vertex lobes are clearly contrasted, widened wedge-shaped with a cut in the center. The cuts in the middle of the cell are not peripherally widened. There exists a big pore in the middle of the cell halves between the two humps. Further humps are visible at the lateral lobes. The cell wall is covered with densely packed pores. Length 150 - 170 µm, width 70 - 85 µm. Occurrence: Adaptable alga, ubiquitous
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Euastrum verrucosum EHRENB. var. groenlandicum (LARSEN) WILLI KRIEG So far only two quite inaccurate illustrations of this alga exist: The original illustration of LARSEN (1904) and an illustration of GROENBLAD (1952). The cell halves are rounded off trapezoidal, both the lateral lobes and the vertex lobe drawn weakly into the center turn into one another, separated only by a shallow emargination. At the ends of the lateral lobes there are several short pricks. The central cuts are far opened. The hump near the isthmus range of the cell halves are covered with large warts, the remaining cell wall with concentric rows of small warts. Length 100 - 105 µm, width 80 - 85 µm. Occurrence: So far only known from Greenland
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Euastrum crassum (BREB.) KÃTZ. The cells are almost two times longer than wide and rounded rectangular in shape. The lateral lobes are broad and rounded off flat concave. The vertex lobes are short and strongly broadened towards the flat recessed ends. They are separated form the lateral lobes only by shallow cuts. The central cuts arenât broadened towards the periphery. At the base of the cell halves there are three swellings with a big pore at their center. Dimension: Length 150 â 200 µm, width 75 â 90 µm Ecology: Acidophilic alga (pH 4 â 6.5), common in shallow sphagnum ponds. Occurrence: Probably ubiquitous
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Euastrum crassum (BREB.) KÃTZ. The cells are almost two times longer than wide and rounded rectangular in shape. The lateral lobes are broad and rounded off flat concave. The vertex lobes are short and strongly broadened towards the flat recessed ends. They are separated form the lateral lobes only by shallow cuts. The central cuts arenât broadened towards the periphery. At the base of the cell halves there are three swellings with a big pore at their center. Dimension: Length 150 â 200 µm, width 75 â 90 µm Ecology: Acidophilic alga (pH 4 â 6.5), common in shallow sphagnum ponds. Occurrence: Probably ubiquitous
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Median optical section through Euastrum crassum using high resolution optics (Planapochromate 40/1.0) and DIC. Sample from sphagnum pond situated in the northern alpine region of Austria near Salzburg. Images were taken using Zeiss Universal with Olympus C7070 CCD camera
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The picture shows the cell wall structure with pores. It is developed using 30 high resolution frames combined with manual stacking technique. Sample from sphagnum pond situated in the northern alpine region of Austria near Salzburg. Images were taken using Zeiss Universal with Olympus C7070 CCD camera.
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Euastrum germanicum (SCHMIDLE) WILLI KRIEG. he cells are only a little longer then wide. The cell halves constist of five broadly rounded lobes. The vertex lobes which are outward somewhat widened are separated from the lobes by extended, inside rounded recessings. Each center of the cell halves showes a hemispheric bump. The cellwall is covered with parallel rows of spines. The central cuts are slender and broadly opened towards the periphery. Dimension: Length 50 â 60 µm, width 40 â 50 µm Ecology: Especially in medium acidic to weakly alcaline waters of ponds and alluvial areas (Danube meadows) Occurrence: Mainly in Europe, but probably ubiquitous
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Euastrum germanicum (SCHMIDLE) WILLI KRIEG. The cells are only a little longer then wide. The cell halves constist of five broadly rounded lobes. The vertex lobes which are outward somewhat widened are separated from the lobes by extended, inside rounded recessings. Each center of the cell halves showes a hemispheric bump. The cellwall is covered with parallel rows of spines. The central cuts are slender and broadly opened towards the periphery. Dimension: Length 50 â 60 µm, width 40 â 50 µm Ecology: Especially in medium acidic to weakly alcaline waters of ponds and alluvial areas (Danube meadows) Occurrence: Mainly in Europe, but probably ubiquitous
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Euastrum intermedium CLEVE The celles are almost two times longer than wide. The cell sides are loboid broadly rounded. The vertex lobes are protruding clearly, broadened on the ends and with a cut in the middle. In the center of the cell halves there are pairs of bumps which are covered with small warts. The central cuts are far opened towards the periphery. Dimension: Length 70 â 80 µm, width 35 â 45 µm Ecology: Acidophilic alga, rather rare in shallow waters between sphagnum. Occurrence: Ubiquitous, prefers boreal areas (mountains), rather rare in Central Europe.
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Euastrum intermedium CLEVE The celles are almost two times longer than wide. The cell sides are loboid broadly rounded. The vertex lobes are protruding clearly, broadened on the ends and with a cut in the middle. In the center of the cell halves there are pairs of bumps which are covered with small warts. The central cuts are far opened towards the periphery. Dimension: Length 70 â 80 µm, width 35 â 45 µm Ecology: Acidophilic alga, rather rare in shallow waters between sphagnum. Occurrence: Ubiquitous, prefers boreal areas (mountains), rather rare in Central Europe.
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Differential interference contrast.
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Euastrum agalma.
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Euastrum pecten.
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