Olaf Hagerup
Encyclopedia
Olaf Hagerup was a Danish
botanist. He studied botany
at the University of Copenhagen
from 1911 under the professors Eugenius Warming
, Christen C. Raunkiær
, L. Kolderup Rosenvinge
og W. Johannsen
. He took his Ph.D. from the same university in 1930. From 1934 to 1960, he was superintendent at the Botanical Museum
of the University of Copenhagen
.
Hagerup’s scientic works concern evolution
, polyploidy
and pollination
, among other things. He showed that the tetraploid Empetrum hermaphroditum is a separate species from the diploid Empetrum nigrum. He thereby initiated the use of chromosome numbers in systematic
botany
, a field later known as cytotaxonomy. He put forward the hypothesis that the ploidy
level is an important factor in the distribution and ecology of plant species. In contrast, another of his scientific ideas has been disproven by later modern research – the idea of a direct ancestry of the centrosperms (approximately equal to Caryophyllales
) from the gymnosperm
ous Gnetophyta
and, hence, two separate evolutionary lineages within the flowering plants. Many of Hagerup’s study were concerned with plant species of the Ericaceae
, Empetraceae and related families, or ’’Bicornes’’ as they were know in the Wettstein system
.
The cranberry
Oxycoccus hagerupii (Ericaceae
) was named to his honour by Á. &
D. Löve
(later transferred to Vaccinium
by Hannu Ahokas as Vaccinium hagerupii.
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
botanist. He studied botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
at the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
from 1911 under the professors Eugenius Warming
Eugenius Warming
Johannes Eugenius Bülow Warming , known as Eugen Warming, was a Danish botanist and a main founding figure of the scientific discipline of ecology...
, Christen C. Raunkiær
Christen C. Raunkiær
Christen Christensen Raunkiær was a Danish botanist, who was a pioneer of plant ecology. He is mainly remembered for his scheme of plant strategies to survive an unfavourable season and his demonstration that the relative abundance of strategies in floras largely corresponded to the Earth's...
, L. Kolderup Rosenvinge
Lauritz Kolderup Rosenvinge
Janus Lauritz Andreas Kolderup Rosenvinge was a Danish botanist and phycologist. He took his Ph.D. 1888 from the University of Copenhagen. He was docent of botany at the polytechnic from 1900, and extraordinary professor of botany the University of Copenhagen with focus on spore plants from 1916...
og W. Johannsen
Wilhelm Johannsen
Wilhelm Johannsen was a Danish botanist, plant physiologist and geneticist. He was born in Copenhagen. While very young, he was apprenticed to a pharmacist and worked in Denmark and Germany beginning in 1872 until passing his pharmacist's exam in 1879...
. He took his Ph.D. from the same university in 1930. From 1934 to 1960, he was superintendent at the Botanical Museum
Copenhagen University Botanical Museum
The Botanical Museum in Copenhagen originated as a part of the Copenhagen Botanical Garden, which was established in 1600. It was later separated as an independent institutiuon...
of the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
.
Hagerup’s scientic works concern evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
, polyploidy
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
and pollination
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
, among other things. He showed that the tetraploid Empetrum hermaphroditum is a separate species from the diploid Empetrum nigrum. He thereby initiated the use of chromosome numbers in systematic
Systematic
Systematic is an American hard rock band from Oakland, California. They were one of the first signings to Metallica drummer Lars Ulrich's record label, The Music Company, via Elektra Records. The band released two studio albums before disbanding in 2004....
botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, a field later known as cytotaxonomy. He put forward the hypothesis that the ploidy
Ploidy
Ploidy is the number of sets of chromosomes in a biological cell.Human sex cells have one complete set of chromosomes from the male or female parent. Sex cells, also called gametes, combine to produce somatic cells. Somatic cells, therefore, have twice as many chromosomes. The haploid number is...
level is an important factor in the distribution and ecology of plant species. In contrast, another of his scientific ideas has been disproven by later modern research – the idea of a direct ancestry of the centrosperms (approximately equal to Caryophyllales
Caryophyllales
Caryophyllales is an order of flowering plants that includes the cacti, carnations, amaranths, ice plants, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves.-Description:...
) from the gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
ous Gnetophyta
Gnetophyta
The plant division Gnetophyta or gnetophytes consists of three genera of woody plants grouped in the gymnosperms. The living Gnetophyta consists of around 70 species across the three genera Gnetum , Welwitschia , and Ephedra .The gnetophytes differ from other gymnosperms The plant division...
and, hence, two separate evolutionary lineages within the flowering plants. Many of Hagerup’s study were concerned with plant species of the Ericaceae
Ericaceae
The Ericaceae, commonly known as the heath or heather family, is a group of mostly calcifuge flowering plants. The family is large, with roughly 4000 species spread across 126 genera, making it the 14th most speciose family of flowering plants...
, Empetraceae and related families, or ’’Bicornes’’ as they were know in the Wettstein system
Wettstein system
A system of plant taxonomy, the Wettstein system recognised the following main groups, according to* I. phylum Schizophyta*::: 1. classis Schizophyceae*::: 2. classis Schizomycetes* II. phylum Monadophyta* III. phylum Myxophyta...
.
The cranberry
Cranberry
Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In some methods of classification, Oxycoccus is regarded as a genus in its own right...
Oxycoccus hagerupii (Ericaceae
Ericaceae
The Ericaceae, commonly known as the heath or heather family, is a group of mostly calcifuge flowering plants. The family is large, with roughly 4000 species spread across 126 genera, making it the 14th most speciose family of flowering plants...
) was named to his honour by Á. &
Áskell Löve
Áskell Löve was an Icelandic systematic botanist, particularly active in the Arctic.Löve was born in Reykjavik. He studied botany at Lund University, Sweden, from 1937. He received his PhD in 1942 in botany and a D.Sc. degree in genetics the year after...
D. Löve
Doris Löve
Doris Benta Maria Löve, née Wahlén was a Swedish systematic botanist, particularly active in the Arctic.Doris Löve was born in Kristianstad, Sweden. She studied botany at Lund University from 1937. She married her fellow student and colleague, the Icelander Áskell Löve. She received her PhD in...
(later transferred to Vaccinium
Vaccinium
Vaccinium is a genus of shrubs or dwarf shrubs in the plant Family Ericaceae. The fruit of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry or whortleberry, lingonberry or cowberry, and huckleberry...
by Hannu Ahokas as Vaccinium hagerupii.
Scientific works
- Hagerup, O. (1915) The structure and biology of arctic flowering plants. 10. CaprifoliaceaeCaprifoliaceaeThe Caprifoliaceae or honeysuckle family is a clade consisting of about 800 dicotyledonous flowering plants, with a nearly cosmopolitan distribution; centres of diversity are found in eastern North America and eastern Asia, while they are absent in tropical and southern Africa.They are mostly...
. Linnaea borealis L. Meddelelser om GrønlandMeddelelser om GrønlandMeddelelser om Grønland was a Danish scientific periodical issued by the Commission for Scientific Investigations in Greenland. Founded by Frederik Johnstrup, it was published from 1879 to 1979...
37: 151-164.
- Hagerup, O. (1922) Om Empetrum nigrumEmpetrum nigrumEmpetrum nigrum is a species of crowberry known as black crowberry which is native to most northern areas of the northern hemisphere, as well as the Falkland Islands in the southern hemisphere....
L. En naturhistorisk Studie (On Empetrum nigrumEmpetrum nigrumEmpetrum nigrum is a species of crowberry known as black crowberry which is native to most northern areas of the northern hemisphere, as well as the Falkland Islands in the southern hemisphere....
L. A study of natural history). Botanisk TidsskriftBotanisk TidsskriftBotanisk Tidsskrift was a Danish mixed scientific and amateur journal concerning botany, issued in Copenhagen by the Danish Botanical Society...
37 (4): 253-304.
- Hagerup, O. (1922) Om "Lobelia-Diagram" hos Erica cinereaErica cinereaErica cinerea is a species of heather, native to western and central Europe. It is a low shrub growing to tall, with fine needle-like leaves long arranged in whorls of three...
L. (On ”Lobelia diagram” by Erica cinereaErica cinereaErica cinerea is a species of heather, native to western and central Europe. It is a low shrub growing to tall, with fine needle-like leaves long arranged in whorls of three...
L.) Botanisk TidsskriftBotanisk TidsskriftBotanisk Tidsskrift was a Danish mixed scientific and amateur journal concerning botany, issued in Copenhagen by the Danish Botanical Society...
38: 137-140.
- Hagerup, O. (1926) Kønsdelenes Bygning og Udvikling hos Koenigia islandica L. (The anatomy and development of sexual structures in Koenigia islandica L.) Meddelelser om GrønlandMeddelelser om GrønlandMeddelelser om Grønland was a Danish scientific periodical issued by the Commission for Scientific Investigations in Greenland. Founded by Frederik Johnstrup, it was published from 1879 to 1979...
58 (3): 197-204.
- Hagerup, O. (1927) Empetrum hermaphroditum (Lge) Hagerup, a new tetraploid, bisexual species. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
5 (2): 1–17.
- Hagerup, O. (1928) Morphological and cytological studies of Bicornes. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
6 (1): 1-27.
- Hagerup, O. (1928) En hygrofil bælgplante (Aeschynomene asperaAeschynomene asperaAeschynomene aspera is a species of flowering plant in the family Fabaceae. It is also known by the names Sola, Sola Pith Plant, Pith Plant, Laugauni or Netti...
L.) med Bakterieknolde paa Stængelen (En hygrophilic legume (Aeschynomene asperaAeschynomene asperaAeschynomene aspera is a species of flowering plant in the family Fabaceae. It is also known by the names Sola, Sola Pith Plant, Pith Plant, Laugauni or Netti...
L.) with bacterial nodules on the stem). Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
5 (14): 1-9.
- Hagerup, O. (1929) Étude des types biologiques de Raunkiær dans la flore autour de TombouctouTombouctouTombouctou may be:* Tombouctou Region in northern Mali* The French name for the city of Timbuktu, which gives its name to the region...
. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 9 (4): 1-116.
- Hagerup, O. (1930) Über die Bedeutung der Schirmform der Krone von Acacia seyal Del. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
6 (4): 1-20.
- Hagerup, O. (1930) Vergleichende Morphologische und Systematische Studien über die Ranken und Andre Vegetative Organe der Cucurbitaceen und Pasifloraceen. Doctoral dissertation, University of CopenhagenUniversity of CopenhagenThe University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
6 (8): 1-104.
- Hagerup, O. (1932) Über Polyploidie in Beziehung zu klima, Ökologie und Phylogenie. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
16: 19-40.
- Hagerup, O. (1932) On Pollination in the extremely hot air at Timbuctu. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
8 (1): 1-20.
- Hagerup, O. (1933) Studies on polyploid ecotypeEcotypeIn evolutionary ecology, an ecotype,Greek: οίκος = home and τύπος = type, coined by Göte Turesson in 1922 sometimes called ecospecies, describes a genetically distinct geographic variety, population or race within species , which is adapted to specific environmental conditions.Typically, ecotypes...
s in Vaccinium uliginosumVaccinium uliginosumVaccinium uliginosum is a flowering plant in the genus Vaccinium.-Distribution:Vaccinium uliginosum is native to cool temperate regions of the Northern Hemisphere, at low altitudes in the Arctic, and at high altitudes south to the Pyrenees, the Alps, and the Caucasus in Europe, the mountains of...
L. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
18 (1-2): 122-128.
- Hagerup, O. (1933) Zur Organogenie und Phylogenie der Koniferenzapfen. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 10 (7).
- Hagerup, O. (1934) Zur Abstammung einiger Angiospermen durch Gnetales und Coniferæ, I. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 11 (4): 1-83.
- Hagerup, O. (1935) Zur Periodizität im Laubwechsel der Moose. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 11 (9): 1-88.
- Hagerup, O. (1936) Zur Abstammung einiger Angiospermen durch Gnetales und Coniferæ, II. Centrospermae. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 13 (6): 1-60.
- Hagerup, O. (1938) On the origin of some Angiosperms through the Gnetales and the Coniferae. III. The gynaeciumGynoeciumGynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
of Salix cinerea. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 14 (4): 1-34.
- Hagerup, O. (1938) A peculiar asymmetrical mitosis in the microspore of OrchisOrchisOrchis is a genus in the orchid family . This genus gets its name from the Ancient Greek ὄρχις orchis, meaning "testicle", from the appearance of the paired subterranean tuberoids....
. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
24: 94-96.
- Hagerup, O. (1938) Studies on the significance of polyploidyPolyploidyPolyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
. II. OrchisOrchisOrchis is a genus in the orchid family . This genus gets its name from the Ancient Greek ὄρχις orchis, meaning "testicle", from the appearance of the paired subterranean tuberoids....
. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
24: 258-264.
- Hagerup, O. (1939) On the origin of some Angiosperms through the Gnetales and the Coniferae. IV. The gynaeciumGynoeciumGynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
of Personatae. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 15 (2): 1-39.
- Hagerup, O. (1939) Studies on the significance of polyploidyPolyploidyPolyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
. III. DeschampsiaDeschampsiaDeschampsia is a genus of grasses in the family Poaceae, commonly known as hair grass or tussock grass. There are 30 to 40 species....
and AiraAiraAira is a genus of about 10 species of annual grasses, native to western and southern Europe, southwest Asia and Africa. The common name, shared with the similar related genera Deschampsia and Koeleria, is Hair-grass, from the very slender leaves and stems...
. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
25: 185-192.
- Hagerup, O. (1940) Studies on the significance of polyploidyPolyploidyPolyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
. IV. Oxycoccus. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
26: 399-410.
- Hagerup, O. (1941) Zytoökologische Bicornes-Studien. Planta 32: 6-14.
- Hagerup, O. (1941) Bestøvningen hos Liparis og MalaxisMalaxisMalaxis, commonly Adder's Mouth, is a genus of terrestrial and semiepiphytic orchids. The generic name signifies "smooth" and alludes to the tender texture of the lamina. There are approximately 250 species....
. (Pollination in Liparis and MalaxisMalaxisMalaxis, commonly Adder's Mouth, is a genus of terrestrial and semiepiphytic orchids. The generic name signifies "smooth" and alludes to the tender texture of the lamina. There are approximately 250 species....
). Botanisk TidsskriftBotanisk TidsskriftBotanisk Tidsskrift was a Danish mixed scientific and amateur journal concerning botany, issued in Copenhagen by the Danish Botanical Society...
45: 396-402.
- Hagerup, O. (1942) The morphology and biology of the Corylus-fruit. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 17 (6): 1-42.
- Hagerup, O. (1942) Myre-Bestøvning. (Ant pollination). Botanisk TidsskriftBotanisk TidsskriftBotanisk Tidsskrift was a Danish mixed scientific and amateur journal concerning botany, issued in Copenhagen by the Danish Botanical Society...
46: 116-123.
- Hagerup, O. (1944) Notes on some boreal polyploids. HereditasHereditasHereditas is a scientific journal concerning genetics. It has been published since 1920 by Mendelska sällskapet i Lund ....
30: 152-160.
- Hagerup, O. (1944) On fertilization, polyploidyPolyploidyPolyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
and haploidy in OrchisDactylorhizaDactylorhiza , is a genus of terrestrial plants in the orchid family ....
maculatus L. sens. lat. Dansk Botanisk ArkivDansk Botanisk ArkivDansk Botanisk Arkiv was a Danish scientific journal or monograph series concerning botany, issued by the Danish Botanical Society. It was published from 1913 to 1980.Articles were written in Danish, German, English and French...
11 (5): 1-26.
- Hagerup, O. (1944) Basidiens cytologi hos Tremellodon gelatinosum (Scop.) Pers. (Cytology of the basidia by Tremellodon gelatinosum (Scop.) Pers). Friesia 3: 46-51.
- Hagerup, O. (1945) Facultative parthenogenesisParthenogenesisParthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
and haploidy in Epipactis latifoliaEpipactis helleborineEpipactis helleborine is a European orchid that has been introduced to several regions of North America. Its nodding flowers vary from greenish pink to purple, and it prefers shaded woodland environments. More information on this species and others of the genus are at Epipactis.-External links:*...
. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 19 (11): 1-14.
- Hagerup, O. (1945) Basidiens cytologi hos Lepiota (LimacellaLimacellaLimacella is a genus of about 20 species of fungi in the Amanitaceae family in order Agaricales. Some of the species have been classified as members of genus Lepiota....
) lenticularis Lasch (Cytology of the basidia by Lepiota (LimacellaLimacellaLimacella is a genus of about 20 species of fungi in the Amanitaceae family in order Agaricales. Some of the species have been classified as members of genus Lepiota....
) lenticularis Lasch). Friesia 3: 96-100.
- Hagerup, O. (1946) Studies on the Empetraceae. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 20 (5): 1-49.
- Hagerup, O. (1947) The spontaneous formation of haploid, polyploid, and aneuploid embryoEmbryoAn embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s in some orchidsOrchidaceaeThe Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 20 (9): 1-22.
- Hagerup, O. (1950) ThripsThripsThrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...
pollinationPollinationPollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
in CallunaCallunaCalluna vulgaris is the sole species in the genus Calluna in the family Ericaceae. It is a low-growing perennial shrub growing to tall, or rarely to and taller, and is found widely in Europe and Asia Minor on acidic soils in open sunny situations and in moderate shade...
. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 18 (4): 1-16.
- Hagerup, O. (1950) Rain-pollinationPollinationPollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 18 (5): 1-18.
- Hagerup, O. (1951) PollinationPollinationPollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
in the Faroes - in spite of rain and poverty in insects. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab 18 (15): 1-48.
- Hagerup, O. (1952) Bud autogamy in some northern orchidsOrchidaceaeThe Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
. Phytomorphology 2: 51-61.
- Hagerup, O. (1952) The morphology and biology of some primitive orchidOrchidaceaeThe Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...
flowers. Phytomorphology 2: 134-138.
- Hagerup, O. (1953) Autogami hos ChamaeorchisChamorchisChamorchis is a genus of flowering plants from the orchid family, Orchidaceae.- References :*Pridgeon, A.M., Cribb, P.J., Chase, M.A. & Rasmussen, F. eds. . Genera Orchidacearum 1. Oxford Univ. Press....
. Blyttia 11: 1-5. - Hagerup, Else & Olaf (1953) Thrips pollination of Erica tetralix. New Phytologist 52 (1): 1-7
- Hagerup, O. (1953) The morphology and systematics of the leaves in EricalesEricalesThe Ericales are a large and diverse order of dicotyledons, including for example tea, persimmon, blueberry, Brazil nut, and azalea. The order includes trees and bushes, lianas and herbaceous plants. Together with ordinary autophytic plants, the Ericales include chlorophyll-deficient...
. Phytomorphology 3: 459-464.
- Hagerup, O. (1953) ThripsThripsThrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...
-pollination in Hypochoeris radicata. Nytt Magasin for Botanik 3: 55-58.
- Hagerup, O. (1954) Autogamy in some drooping Bicornes flowers. Botanisk TidsskriftBotanisk TidsskriftBotanisk Tidsskrift was a Danish mixed scientific and amateur journal concerning botany, issued in Copenhagen by the Danish Botanical Society...
51: 103-116. - Hagerup, O. (1957) Wind autogamy in Arbutus. Bulletin du Jardin botanique de l'État a Bruxelles 27 (1): 41-47.
- Hagerup, Olaf & Petersson, Vagn (1956–1960) Botanical Atlas. Copenhagen: Munksgaard.
- Vol. I: Angiosperms, 550 p.
- Vol. II: MossMossMosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es, FernFernA fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s, HorsetailsEquisetaceaeEquisetaceae, sometimes called the horsetail family, is the only extant family of the class Equisetales, with one surviving genus, Equisetum, which comprises about twenty species.- Evolution and systematics :...
, ClubmossesLycopodiaceaeThe Lycopodiaceae is a family of primitive vascular plants, including all of the core clubmosses. These plants bear spores on specialized structures at the apex of a shoot; they resemble a tiny battle club, from which the common name derives...
, Conifers, EvolutionEvolutionEvolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
. 299 p.