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Euastrum gemmatum (BREB.) BREB. var. alatum KOSSINSAJA The cells are appr. 1.5 times longer than wide and.squarely shaped in the center section. Due to an emargination the lateral line of the shape shows two lobes. The vertex lobes are broadened towards the periphery, rounded on the lateral line and slightly concave in the center of the lobe. The cut in the middle of the cell is deep and peripherally widened. In the center of the cell halves there is a clear hump with small verrucae, on both sides of this hump there is a further, flat hump. This area together with the lateral lobes and the vertex lobes are clearly covered with tiny warts. Length 55 - 60 µm, width 45 - 50 µm. Occurrence: Not rare also in weakly acidic ponds in the alpine regions up to an altitude of 2000 m
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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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Staurastrum gratum WHELDEN The cells are 1/3 longer than wide coarsely oval in shape, tri-radial, but similar to a Cosmarium. Thr central cuts are shallow, the cell edges with small waves. The cell wall is covered with concentric rings of small warts. The vertex view is triangular with broadly rounded off ends. Length 40 µm, width 30 µm. Occurrence: Known only from northern areas (Baffin Island ans Labrador).
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Xanthidium antilopaeum (BREB.) KÃTZ. var. crameri GRÃNBLAD The cells are a little wider than long and octagonal in coarse shape. The central cut is deep and extends strongly outwards. The cell halves are oblong hexagonal with straight or weakly concave sides, the vertices are broadly truncated. At each lateral and apical angle a pair of long pricks originate. Above the center is a flat, often slightly brown colored swelling of the cell wall occupies with small warts. Length without pricks 50 - 60 µm, width without pricks 58 - 63 µm. Occurrence: In littoral zones of mountain lakes in Central Europe rather rarely.
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Xanthidium antilopaeum (BREB.) KÃTZ. var. crameri GRÃNBLAD The cells are a little wider than long and octagonal in coarse shape. The central cut is deep and extends strongly outwards. The cell halves are oblong hexagonal with straight or weakly concave sides, the vertices are broadly truncated. At each lateral and apical angle a pair of long pricks originate. Above the center is a flat, often slightly brown colored swelling of the cell wall occupies with small warts. Length without pricks 50 - 60 µm, width without pricks 58 - 63 µm. Occurrence: In littoral zones of mountain lakes in Central Europe rather rarely.
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Xanthidium cristatum BREB. In RALFS The cells are little longer than wide, octagonal in coarse shape with straight or weakly concave sides. The central cut is strongly extended outwards. On each side of each cell half origins one prick . The lateral and apical angles likewise have one pair of pricks each. In the center of the cell halves is flat, hemispheric swelling. Length without pricks 50 - 55 µm, width without pricks 40 - 43 µm. Occurrence: In Central Europe sporadic in moderate acidic waters of fens, siltation zones et cetera.
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Xanthidium cristatum BREB. In RALFS The cells are little longer than wide, octagonal in coarse shape with straight or weakly concave sides. The central cut is strongly extended outwards. On each side of each cell half origins one prick . The lateral and apical angles likewise have one pair of pricks each. In the center of the cell halves is flat, hemispheric swelling. Length without pricks 50 - 55 µm, width without pricks 40 - 43 µm. Occurrence: In Central Europe sporadic in moderate acidic waters of fens, siltation zones et cetera.
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Xanthidium groenlandicum BOLD fa. depauperata LARSEN The cells are little wider than long and almost square in shape. The central cut is deep and extends strongly outwards. The cell halves are stretched octagonally with broadly rounded ends. At the cell sides there are two broadly blunted, conical extensions and a hardly visible projection on both sides of the cell vertices. In the center of the cell halves is a flat swelling, which is covered with small warts or dimples. From this alga only three illustrations exist so far: BOLDT (1888), LARSEN (1907) und GRÃNBLAD (1952). Length 60 - 63 µm, width 65 - 68 µm. Occurrence: Known only from Greenland so far.
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Micrasterias is one of the desmids, flattened green algae in which the organism has a central constriction which gives the organism the appearance of being two cells joined together. Phase contrast micrograph.
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Micrasterias is one of the desmids, flattened green algae in which the organism has a central constriction which gives the organism the appearance of being two cells joined together. Differential interference contrast.
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Micrasterias radiosa (RALFS,1848). M. sol (EHRENBERG ex KÅ°TZING,1849) is a junior synonym. Phase contrast.
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Docidium undulatum BAIL. The cells are 15-25 times longer than wide with truncated ends. The sides are repeatedly flatly undulated. The central cut is little formed. On both sides around the cut runs a ring with tiny, broadly rounded nipples. Dimension: Length 200 â 250 µm, width 12 â 17 µm Ecology: Acidophilic alga, in acidic fens together with Micrasterias jenneri, Micrasterias truncata und Euastrum armatum. Occurrence: Ubiquitous
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Docidium undulatum BAIL. The cells are 15-25 times longer than wide with truncated ends. The sides are repeatedly flatly undulated. The central cut is little formed. On both sides around the cut runs a ring with tiny, broadly rounded nipples. Dimension: Length 200 â 250 µm, width 12 â 17 µm Ecology: Acidophilic alga, in acidic fens together with Micrasterias jenneri, Micrasterias truncata und Euastrum armatum. Occurrence: Ubiquitous
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Euastrum attenuatum WOLLE var. splendens (F.E.FRITSCH & RICH.) GRÃNBLAD The cells are almost two times longer than wide. The cell halves have three lobes, the lateral lobes are broad and shallowly undulated at the ends. The vertex lobes are widened at the ends and are surrounded with a collar of warts. In the center of each cell half and on both sides of them there are broad swellings. The central cuts open outwards in an acute-angle. . Dimension: Length 57 â 60 µm, width 33 â 35 µm Ecology: In shallow, moderate acidic waters of fens and bogs. Occurrence: South America (Anden up to altitude of 3000 m toTierra del Fuego), Africa (Natal, Sudan), firstly recorded for Europe!
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Euastrum attenuatum WOLLE var. splendens (F.E.FRITSCH & RICH.) GRÃNBLAD The cells are almost two times longer than wide. The cell halves have three lobes, the lateral lobes are broad and shallowly undulated at the ends. The vertex lobes are widened at the ends and are surrounded with a collar of warts. In the center of each cell half and on both sides of them there are broad swellings. The central cuts open outwards in an acute-angle. . Dimension: Length 57 â 60 µm, width 33 â 35 µm Ecology: In shallow, moderate acidic waters of fens and bogs. Occurrence: South America (Anden up to altitude of 3000 m toTierra del Fuego), Africa (Natal, Sudan), firstly recorded for Europe!
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Euastrum crameri RACIB. The cells are appr. 1.5 times longer than wide and trapezoidal in shape. The cell sides are formed by flat depressions from two distinct waves.The vertex lobes are clearly separated, strongly broadened towards the ends. They have a central cut with a spine each on the sides. The central cut of the cell is narrow, the cellwall is covered with warts and denticles. Dimension: Length 60 â 65 µm, width 45 â 50 µm Ecology: Sporadic in medium acidic waters of fens and moorlands Occurrence: Rather rare, most of the reported finds are in northern areas and higher altitudes.
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Euastrum crameri RACIB. The cells are appr. 1.5 times longer than wide and trapezoidal in shape. The cell sides are formed by flat depressions from two distinct waves.The vertex lobes are clearly separated, strongly broadened towards the ends. They have a central cut with a spine each on the sides. The central cut of the cell is narrow, the cellwall is covered with warts and denticles. Dimension: Length 60 â 65 µm, width 45 â 50 µm Ecology: Sporadic in medium acidic waters of fens and moorlands Occurrence: Rather rare, most of the reported finds are in northern areas and higher altitudes.
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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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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.