Hagerup’s scientific works concern
evolution,
polyploidy and
pollination, among other things. He showed that the
tetraploidEmpetrum hermaphroditum is a separate species from the
diploidEmpetrum nigrum. He thereby initiated the use of
chromosome numbers in
systematicbotany, 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
gymnospermousGnetophyta and, hence, two separate evolutionary lineages within the
flowering plants. Many of Hagerup’s studies were concerned with plant species of the
Ericaceae,
Empetraceae and related families, or ’’Bicornes’’ as they were known in the
Wettstein system.
Hagerup, O. (1930) Über die Bedeutung der Schirmform der Krone von Acacia seyal Del.
Dansk Botanisk Arkiv 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 Copenhagen.
Dansk Botanisk Arkiv 6 (8): 1-104.
Hagerup, O. (1932) Über Polyploidie in Beziehung zu klima, Ökologie und Phylogenie.
Hereditas 16: 19-40.
Hagerup, O. (1934) Zur Abstammung einiger Angiospermen durch Gnetales und Coniferæ, I. Biologiske Meddelelser,
Kongelige Danske Videnskabernes Selskab 11 (4): 1-83.
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. (1944) Basidiens cytologi hos Tremellodon gelatinosum (Scop.) Pers. (Cytology of the basidia by Tremellodon gelatinosum (Scop.) Pers). Friesia 3: 46-51.
Hagerup, O. (1945) Basidiens cytologi hos Lepiota (
Limacella) lenticularis Lasch (Cytology of the basidia by Lepiota (
Limacella) lenticularis Lasch). Friesia 3: 96-100.
Hagerup’s scientific works concern
evolution,
polyploidy and
pollination, among other things. He showed that the
tetraploidEmpetrum hermaphroditum is a separate species from the
diploidEmpetrum nigrum. He thereby initiated the use of
chromosome numbers in
systematicbotany, 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
gymnospermousGnetophyta and, hence, two separate evolutionary lineages within the
flowering plants. Many of Hagerup’s studies were concerned with plant species of the
Ericaceae,
Empetraceae and related families, or ’’Bicornes’’ as they were known in the
Wettstein system.
Hagerup, O. (1930) Über die Bedeutung der Schirmform der Krone von Acacia seyal Del.
Dansk Botanisk Arkiv 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 Copenhagen.
Dansk Botanisk Arkiv 6 (8): 1-104.
Hagerup, O. (1932) Über Polyploidie in Beziehung zu klima, Ökologie und Phylogenie.
Hereditas 16: 19-40.
Hagerup, O. (1934) Zur Abstammung einiger Angiospermen durch Gnetales und Coniferæ, I. Biologiske Meddelelser,
Kongelige Danske Videnskabernes Selskab 11 (4): 1-83.
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. (1944) Basidiens cytologi hos Tremellodon gelatinosum (Scop.) Pers. (Cytology of the basidia by Tremellodon gelatinosum (Scop.) Pers). Friesia 3: 46-51.
Hagerup, O. (1945) Basidiens cytologi hos Lepiota (
Limacella) lenticularis Lasch (Cytology of the basidia by Lepiota (
Limacella) lenticularis Lasch). Friesia 3: 96-100.