Carl Frederik Albert Christensen (16 January 1872 – 24 November 1942) was a Danish systematic botanist. He graduated in natural history from the University of Copenhagen under professor Eugenius Warming. He was first school teacher in Copenhagen, later superintendent at the Botanical Museum. He was a specialist in ferns and published a catalogue of the World's Pteridophytes, Index Filicum. In addition, he authored a three-volume work on the history of botany in Denmark.
Selected scientific works
- Christensen, Carl (1905–06) Index Filicum. 744 s. Index Filicum Supplementum I-III (1913–17). Reprint 1973 by Koeltz Antiquariat.
- Christensen, Carl (1924-1926) Den danske botaniks historie med tilhørende Bibliografi. København, H. Hagerups Forlag. Three vols. 680 s.
- Pichi-Sermolli, R. (1946). "Carl Christensen in memoriam (1872–1942)". Nuovo Giornale Botanico Italiano. nueva serie 53 (1-2).
- Benedict, R. C. (1912). "Carl Frederik Albert Christensen: Some Biographical Notes". American Fern Journal 2 (2): 53–57. JSTOR 1544606.
- Asplund, E. (1945). "Carl Christensen". American Fern Journal 35 (4): 131–132. JSTOR 1545652.