| 1951 | Herbarium Image: Elodea sp. |
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| 1952 | Rhizophydium |
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| 1953 | Melosira, |
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| 1954 | Herbarium Image: Myosotis scorpioides |
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| 1955 | Ceraclea dissimilis larva, |
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| 1956 | Pleurotaenium, |
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| 1957 | Herbarium Image: Rorippa islandica |
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| 1958 | Gyrosigma, |
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| 1959 | Syngenta Pond Physchem Data (2003) |
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| 1960 | Heptagenia fuscogrisea |
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| 1961 | Peridinium, |
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| 1962 | Prymnesium |
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| 1963 | Gomphosphaeria, |
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| 1964 | Porphyridium, |
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| 1965 | Uroglena volvox |
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| 1966 | Herbarium Image: Mimulus luteus |
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| 1967 | Herbarium Image: Nitella opaca |
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| 1968 | Herbarium Image: Nitella opaca |
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| 1969 | Herbarium Image: Potamogeton perfoliatus |
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| 1970 | Herbarium Image: Oenanthe fluviatilis |
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| 1971 | Nostoc, |
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| 1972 | Herbarium Image: Potamogeton crispus |
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| 1973 | Trentepohlia, |
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| 1974 | Herbarium Image: Potamogeton gramineus |
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| 1975 | Prymnesium |
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