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

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

and explorer. As a botanist his interests included

pteridology The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

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 botanists who have an active interest in observing, recording, classifying ...

, and

paleobotany Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments ( pal ...

. He made botanical expeditions to

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. During his expeditions to Greenland, he visited

Disko Island Disko Island (, ) is a large island in Baffin Bay, off the west coast of Greenland. It has an area of ,horsetail ''Equisetum'' (; horsetail) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass Equisetidae, which ...

s and

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

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 Southwest 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 ...

on the west coast of

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

. Later, these fossils were studied by the German paleobotanist Paul J. Menzel (1864–1927). Dusén edited three exsiccatae devoted to bryophytes, among them one with the title ''Musci Africani in Camerunia a P. Dusén collecti'' (1893) and another work with the title ''Hepaticae Africanae in Camerunia a P. Dusén collectae''. 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 A herbarium (plural: herbaria) is a collection of preserved plant biological specimen, specimens and associated data used for scientific study. The specimens may be whole plants or plant parts; these will usually be in dried form mounted on a sh ...

Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...

in 1945.

Honours

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

Acanthaceae Acanthaceae () is a Family (biology), family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are Tropics, tropical Herbaceous plant, herbs, shrubs, or twining vines; some are epip ...

) '' 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 p ...

) '' 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'' (Turcz ...

'' (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 lacertoidean 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 Gymnophthalmidae, Gymnopthalmidae, and ...

) ''

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 c ...

'' 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 19th-century Swedish botanists {{Sweden-botanist-stub