Peter Nielsen (botanist) explained

Peter Nielsen (28 July 1829 – 30 September 1897) was a Danish botanist and plant pathologist.^[1]

He was born at a farm in Vonsbæk parish in the Duchy of Schleswig. He graduated in 1857 from Jelling Statsseminarium in Vejle. He was employed at Flakkebjerg Institute from 1857-1859. In 1859, he became a school teacher at Ørslev in Zealand, where he studied the local flora. He was particularly interested in plants useful to agriculture and in plant pathogens. He was a prolific writer on these topics. He undertook meticulous studies of rust fungi.^{[2] [3] [4]}

He was the first to describe the host alternation of Puccinia poarum between grasses and Tussilago farfara.^[5]

Notes and References

1. http://www.indexfungorum.org/Names/AuthorDetails.asp?ID=979 Index Fungorum Authors of Fungal Names
2. Web site: Nielsen, Peter, dansk landøkonomisk Forsøgsleder . Salmonsens konversationsleksikon . January 1, 2020.
3. Web site: Jelling Statsseminarium. Den Store Danske, Gyldendal . Tage Kampmann . January 1, 2020.
4. “Peter Nielsen”, pp. 221-223 in Warming . Eug. . Eugenius Warming . 1881 . Den danske botaniske Literatur fra de ældste Tider til 1880 . Danish . Danish botanical literature from ancient times to 1880 . . 12 . 42–217 .
5. Nielsen . P. . 1877 . Bemærkninger om nogle Rustarter, navnlig om en genetisk Forbindelse mellem Aecidium tussilaginis Pers. og Puccinia poarum n. sp. . Danish . Notes on some rust species, in particular the genetic unity of Aecidium tussilaginis Pers. and Puccinia poarum n. sp. . . 10 . 26–42 .