astronomy

Per Magnus Jørgensen

Per Magnus Jørgensen is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Per Magnus Jørgensen rather than just read about it. In short: Per Magnus Jørgensen (born 1944) is a Norwegian botanist and lichenologist, and Professor Emeritus of systematic botany at the University of Bergen. He is known for his work on the lichen families Pannariaceae and Collemataceae.

Key takeaways

Per Magnus Jørgensen belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Per Magnus Jørgensen to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Per Magnus Jørgensen from memory before moving on to harder problems.

Reference excerpt

Per Magnus Jørgensen (born 1944) is a Norwegian botanist and lichenologist, and Professor Emeritus of systematic botany at the University of Bergen. He is known for his work on the lichen families Pannariaceae and Collemataceae. Jørgensen was awarded the Acharius Medal in 2021 for his lifetime contributions to lichenology.

Biography Jørgensen was born in Stavanger, Norway, in 1944. He obtained his Candidatus realium from the University of Bergen in 1969, where Knut Fægri was his supervisor. In 1978, he earned a doctor philosophiae from University of Bergen, with a dissertation titled "The lichen family Pannariaceae in Europe". He was a student of prominent lichenologist Rolf Santesson; Gunnar Degelius was another early mentor. During his time as a student, he was recruited to work at the Botanical Garden in Bergen. A few years after receiving his doctorate, he was appointed Professor of Systematic Botany at the University of Bergen in 1982. He was known for delivering his university lectures with great enthusiasm, and for helping to popularize botany in Norway. As of 2020, he is a Professor Emeritus at the University of Bergen. Jørgensen is a member of the Norwegian Academy of Sciences. He has about 300 publications dealing with the systematics, floristics, biogeography, and nomenclature of lichens; in these papers he described about 300 taxa new to science. A specialist of the family Pannariaceae, he has also written about several other families in the third volume of the Nordic Lichen Flora. More recently, he has published several works about the history of lichenology. Examples include books on the history of botany in Norway, and on the history of Bergen's Museumgarden, and publications on Carl Linnaeus and Johan Ernst Gunnerus, including translating the latter's 1770 work Flora Norvegica from Latin into Norwegian. Jørgensen is a connoisseur of the plant genus Rhododendron and maintains a large collection of these plants in the Bergen botanical garden. He was editor of the popular science magazine Naturen from 1991 to 1997. Jørgensen became an honorary lifetime member of the British Lichen Society in 2008. In 2021 Jørgensen was awarded the Acharius Medal, recognizing his lifelong contribution to lichenology. Lichen taxa named in honour of Jørgensen include the species Stigmidium joergensenii R.Sant. (1989), Leptogium joergensenii Marcelli & Kitaura (2014), and the genus Joergensenia Passo, S.Stenroos & Calvelo (2008).

Selected publications Jørgensen, Per M. (1978). The Lichen Family Pannariaceae in Europe. Opera Botanica. Vol. 45. Stockholm: Swedish Natural Science Research Council. pp. 1–123. Jørgensen, Per M.; James, Peter W.; Jarvis, Charles E. (1994). "Linnaean lichen names and their typification". Botanical Journal of the Linnean Society. 115 (4): 261–405. doi:10.1111/j.1095-8339.1994.tb01784.x. Jørgensen, Per M. (2001). "Great discoveries in bryology and lichenology: Th. M. Fries (1832–1913), great Scandinavian lichenologist". The Bryologist. 104 (4): 537–542. doi:10.1639/0007-2745(2001)104[0537:TMFAGS]2.0.CO;2. JSTOR 3244587. Jørgensen, Per M. (2002). Conspectus familiae Pannariaceae (Ascomycetes lichenosae) (PDF). Ilicifolia. Vol. 4. Bergen: Botanisk institutt, Universitetet i Bergen. pp. 1–78. ISBN 82-7460-014-2. Jørgensen, Per M. (2007). "History of lichenology in Norway up to 1973". Bibliotheca Lichenologica. 95: 41–61. Jørgensen, Per M., ed. (2007). Botanikkens historie i Norge [History of Botany in Norway] (in Norwegian). Bergen: Fagbokforlaget Vignostad & Bjoeke AS. ISBN 978-82-450-04991. Jørgensen, Per M. (2017). "The development of lichenology in the history of botany". The Bryologist. 120 (1): 37–44. doi:10.1639/0007-2745-120.1.037. S2CID 90626078.

See also Category:Taxa named by Per Magnus Jørgensen

References

Cited literature Hertel, Hannes; Gärtner, Georg; Lőkös, László (2017). "Forscher an Österreichs Flechtenflora" [Investigators of Austria's lichen flora] (PDF). Stapfia (in German). 104 (2): 1–211. Kärnefelt, Ingvar (2009). "Fifty influential lichenologists". In Thell, Arne; Seaward, Mark R. D.; Feuerer, Tassilo (eds.). Diversity of Lichenology – Anniversary Volume. Bibliotheca Lichenologica. Vol. 100. Stuttgart: J. Kramer. pp. 283–368. ISBN 978-3-443-58079-7.

Worked examples

Example 1 — a first encounter with Per Magnus Jørgensen

Start with the simplest possible case. Write down what Per Magnus Jørgensen claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Per Magnus Jørgensen before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Per Magnus Jørgensen ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Per Magnus Jørgensen

In research: Per Magnus Jørgensen appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Per Magnus Jørgensen in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Per Magnus Jørgensen is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1944 births, 20th-century Norwegian botanists, 21st-century Norwegian botanists, so understanding it makes those chapters shorter.
In everyday life: Look for Per Magnus Jørgensen outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Per Magnus Jørgensen” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Per Magnus Jørgensen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Per Magnus Jørgensen means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Per Magnus Jørgensen out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Per Magnus Jørgensen in simple terms?

Why does Per Magnus Jørgensen matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Per Magnus Jørgensen?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Per Magnus Jørgensen.