{{Short description|Swedish botanist}} {{Use dmy dates|date=April 2025}} {{Use Oxford spelling|date=April 2025}} {{Infobox person | name = Nils Gustaf Lagerheim | image = Gustaf Lagerheim.jpg | alt = A portrait of Nils Gustaf Lagerheim | birth_date = {{birth date|1860|10|18|df=yes}} | birth_place = Stockholm, Sweden | death_date = {{death date|1926|1|2|df=yes}} | death_place = Stockholm, Sweden | occupation = Botanist | alma_mater = Upsala university | spouse = Céline Julie Berthe Devéria }}
'''Nils Gustaf Lagerheim''' (1860–1926) was a Swedish botanist, mycologist, phycologist, and pteridologist.<ref>{{cite book|last=Grummann|first=Vitus|date=1966|title=Biographisch-bibliographisches Handbuch d. Lichenolgie}}</ref> Today, he is best remembered as one of the chief architects of pollen analysis as a tool in botany, alongside his student Ernst Post.
==Career and expeditions==
After graduating from Uppsala University in 1885 Lagerheim was appointed assistant in the botanical department of the Swedish Museum of Natural History, where he specialised in freshwater algae and rust fungi.<ref name="SBL" /> In 1889–91 he undertook a collecting expedition to Ecuador and Bolivia sponsored by the Royal Academy of Sciences; the 12,000 specimens he brought back included 45 new orchid species and formed the nucleus of the museum's South-American herbarium.<ref name="SBL"/> His lichen and rust collections from that trip were later studied by William Nylander and Paul Sydow, respectively, who introduced more than 70 taxa bearing the epithet ''lagerheimii''.<ref name="Westman 1927"/>
With Veit Brecher Wittrock and Otto Nordstedt he edited the exsiccata series {{lang|la|Algae aquae dulcis exsiccatae praecipue Scandinavicae quas adjectis algis marinis Chlorophyllaceis et Phycochromaceis distribuerunt Veit Wittrock, Otto Nordstedt, G. Lagerheim}} ({{gloss|Dried freshwater algae, chiefly from Scandinavia, with additional marine green and brown algae, distributed by Veit Wittrock, Otto Nordstedt and G. Lagerheim}}, 1896–1903).<ref>{{cite web |title=Algae aquae dulcis exsiccatae praecipue Scandinavicae quas adjectis algis marinis Chlorophyllaceis et Phycochromaceis distribuerunt Veit Wittrock, Otto Nordstedt, G. Lagerheim: IndExs ExsiccataID=714101888 |website=IndExs – Index of Exsiccatae |publisher=Botanische Staatssammlung München |url=https://www.botanischestaatssammlung.de/DatabaseClients/IndExs/Exsiccatae_IndExs_Details.jsp?ExsiccataID=714101888 |access-date=13 August 2024}}</ref><ref name="Triebel & Scholz 2001-2024">Triebel, D. & Scholz, P. 2001–2024 ''IndExs – Index of Exsiccatae''. Botanische Staatssammlung München: http://indexs.botanischestaatssammlung.de. – München, Germany.</ref>
==Pollen analysis pioneer==
While curator at the museum (1893–1907) Lagerheim investigated fossil pollen in peat cores from Uppland iron-age sites. In a 1902 paper he plotted percentage curves of spruce and alder pollen versus depth—an idea taken up by his student Ernst Post and now regarded as the first true pollen diagram, laying a foundation for modern Quaternary palaeoecology.<ref name="Edwards 2017"/>
==Academic posts and legacy==
In 1907 he became professor of botany at the newly established Royal Swedish Agricultural College in Stockholm, restructuring the curriculum to include plant pathology and mycology for agronomists. He described more than 200 algal species. The green-algal genera ''Lagerheimia'' (1895) and ''Lagerheimiella'' (1940) commemorate his contributions. At his death in 1926 the Nationalmuseum catalogue credited him with 175 publications spanning botany, mycology, phycology and palaeoecology.<ref name="Westman 1927"/>
{{botanist|Lagerh.|inline=yes}}
==References== {{Reflist|refs=
<ref name="SBL">{{cite encyclopedia |title=Lagerheim, Nils Gustaf |encyclopedia=Svenskt biografiskt lexikon |url=https://sok.riksarkivet.se/sbl/Presentation.aspx?id=10350 |publisher=Riksarkivet |language=sv |access-date=29 April 2025}}</ref>
<ref name="Edwards 2017">{{cite journal |last1=Edwards |first1=Kevin J. |last2=Fyfe |first2=R. Matthew |last3=Jackson |first3=Stephen T. |year=2017 |title=The first 100 years of pollen analysis |journal=Nature Plants |volume=3 |issue=2 |pages=17001 |doi=10.1038/nplants.2017.1 |pmid=28145493|pmc=5296638 |bibcode=2017NatPl...317001E |hdl=2164/9078 |hdl-access=free }}</ref>
<ref name="Westman 1927">{{cite journal |last=Westman |first=Henrik |year=1927 |title=Nils G. Lagerheim in memoriam |journal=Svensk Botanisk Tidskrift |volume=21 |pages=1–12}}</ref>
}}
{{Commons category|Nils Gustaf Lagerheim}} {{authority control}}
{{DEFAULTSORT:Lagerheim, Nils Gustaf}} Category:19th-century Swedish botanists Category:Swedish mycologists Category:Swedish phycologists Category:1860 births Category:1926 deaths Category:Scientists from Stockholm