- Thorvald Sørensen
Thorvald Julius Sørensen (1902–1973) was a Danish
botanist and evolutionary biologist.Sørensen was professor at the Royal Veterinary and Agricultural College 1953-1955 and at the
University of Copenhagen 1955-1972. He was director of theCopenhagen Botanical Garden and Botanical Museum during the same period.Thorvald Sørensen spent the years 1931-1935, based on
Ella Island , studying plants in the then little known North-EastGreenland . He published a doctoral thesis on the annual phenological rhythm of the High Arctic plant species, including thepollination of their flowers (1941).He critically revised the
Greenland flora and sorted outtaxonomy of a number of difficult taxa, most notablyPuccinellia .He carried out a number of studies in the
evolutionary biology of plants, such asTaraxacum ,Capsella bursa-pastoris andRanunculus .He developed a quotient of similarity in species composition between plant communities - the still much-used
Sørensen similarity index . He illustrated its use on a data set collected in Danishgrassland byJohannes Grøntved , who used Raunkiær's quantitative method to sample vegetation.Example of plant name he published:
*"Braya intermedia" T.J.Sørensen (1954) inMeddelelser om Grønland 134 (8).
*"Puccinellia groenlandica" T.J.Sørensen (1953) inMeddelelser om Grønland 134 (3).ources
*Obituary in
Botanisk Tidsskrift 68 (2): 165-168 (1973)elected scientific works
* Sørensen, T. (1935) Bodenformen und Pfanzendecke in Nordostgrönland. Beiträge zur Theorie der polaren Bodenversetzungen auf Grund von Beobachtungen über deren Einfluss auf die Vegetation in Nordostgrönland.
Meddelelser om Grønland 93 (4).*Sørensen, T. (1941) Temperature relations and
phenology of the NortheastGreenland flowering plants.Meddelelser om Grønland 129: 1-305.*Sørensen, T. (1942) Untersuchungen über die Therophytengesellschaften auf den isländischen Lehmflächen ("Flags"). Biologiske Skrifter /
Kongelige Danske Videnskabernes Selskab 2 (2).*Sørensen, T. and Gudjónsson, Gudni (1946) Spontaneous chromosome-aberrants in apomictic Taraxaca: morphological and cyto-genetical investigations. Biologiske Skrifter /
Kongelige Danske Videnskabernes Selskab 4 (2).*Sørensen, T. (1948) A method of establishing groups of equal amplitude in plant sociology based on similarity of species and its application to analyses of the vegetation on Danish commons. Biologiske Skrifter /
Kongelige Danske Videnskabernes Selskab 5: 1-34.*Sørensen, T. (1953) A Revision of the Greenland Species of "
Puccinellia " Parl. With contribution to our knowledge of the Arctic "Puccinellia " flora in general.Meddelelser om Grønland 136 (3) 1-179.*Jørgensen, C.A., Sørensen, T. and Westergaard, M. (1958) The Flowering Plants of Greenland. Biologiske Skrifter /
Kongelige Danske Videnskabernes Selskab 9 (4).
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