Per Karl Hjalmar Dusén (1855–1926) was a Swedish civil engineer,

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

and explorer. As a botanist his interests included

pteridology A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except th ...

bryology Bryology (from Greek , a moss, a liverwort) is the branch of botany concerned with the scientific study of bryophytes (mosses, liverworts, and hornworts). Bryologists are people who have an active interest in observing, recording, classifying or ...

, and

paleobotany Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeogr ...

. He made botanical expeditions to

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. During his expeditions to Greenland, he visited

Disko Island Disko Island ( kl, Qeqertarsuaq, da, Diskoøen) is a large island in Baffin Bay, off the west coast of Greenland. It has an area of ,horsetail ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns, which reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass Eq ...

s and

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

s. Between 1890 and 1892, Dusén collected nearly 560 leaf fossils preserved in

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

in the vicinity of

Mount Cameroon Mount Cameroon is an active volcano in the South West region of Cameroon next to the city of Buea near the Gulf of Guinea. Mount Cameroon is also known as Cameroon Mountain or Fako (the name of the higher of its two peaks) or by its indigenous n ...

on the west coast of

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

. Later, these fossils were studied by the German paleobotanist Paul J. Menzel (1864–1927). His botanical specimens are at the

New York Botanical Garden The New York Botanical Garden (NYBG) is a botanical garden at Bronx Park in the Bronx, New York City. Established in 1891, it is located on a site that contains a landscape with over one million living plants; the Enid A. Haupt Conservatory, ...

, being obtained when they acquired the herbarium of

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

in 1945.

Honours

More than 200 species were named in his honour, including: * (

Acanthaceae Acanthaceae is a family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are tropical herbs, shrubs, or twining vines; some are epiphytes. Only a few species are distributed in te ...

) '' Acanthus dusenii'' C.B.Clarke * (Acanthaceae) '' Justicia dusenii'' (Lindau) Wassh. & L.B.Sm. in Reitz * (

Anacardiaceae The Anacardiaceae, commonly known as the cashew family or sumac family, are a family of flowering plants, including about 83 genera with about 860 known species. Members of the Anacardiaceae bear fruits that are drupes and in some cases produce ...

) '' Trichoscypha dusenii'' Engl. * (

Annonaceae The Annonaceae are a Family (biology), family of flowering plants consisting of trees, shrubs, or rarely lianas commonly known as the custard apple family or soursop family. With 108 accepted genera and about 2400 known species, it is the largest ...

) '' Guatteria dusenii'' R.E.Fr. * (

Apiaceae Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus ''Apium'' and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plants ...

) '' Azorella dusenii'' H.Wolff * (Apiaceae) '' Centella dusenii'' Nannf. * (Apiaceae) ''

Trachymene dusenii '' Trachymene coerulea'' (Australian lace flower) ''Trachymene'' is a genus of herbaceous plants in the family Araliaceae. The species are native to Australia, Malesia, New Caledonia and Fiji. Species include: *'' Trachymene anisocarpa'' ( ...

'' (Domin) B.L.Burtt * (

Aspleniaceae The Aspleniaceae (spleenworts) are a family of ferns, included in the order Polypodiales. The composition and classification of the family have been subject to considerable changes. In particular, there is a narrow circumscription, Aspleniaceae ...

) '' Asplenium dusenii'' Luerss. * (

Teiidae Teiidae is a family of autarchoglossan lizards native to the Americas. Members of this family are generally known as whiptails or racerunners; however, tegus also belong to this family. Teiidae is sister to the Gymnopthalmidae, and both families ...

) ''

Salvator duseni ''Salvator duseni'' is a species of lizard in the family Teiidae. The species is sometimes known commonly as the yellow tegu. It is native to South America. Etymology ''S. duseni'' is named after Swedish botanist Per Karl Hjalmar Dusén who ...

'' Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . ("Dusen", p. 78). Dusén Fjord in northeastern Greenland was named in his honour.

References

1855 births 1926 deaths Swedish botanists {{Sweden-botanist-stub