Ostenfeld, C.H. & Johannes Schmidt Plankton fra det Røde Hav og Adenbugten. Videnskabelige meddelelser fra Dansk Naturhistorisk Forening 1901: 141-182.
Gelert, O. & Ostenfeld, C.H. Flora Arctica - containing description of the flowering plants and ferns, found in the Arctic regions, with their distribution in these countries, illustrated by numerous figures in the text.
*Part 1. Pteridophyta, Gymnospermae and Monocotyledones. Copenhagen, 1902.
Ostenfeld CH, Rosenberg O Experimental and cytological studies in the Hieracia. I. Castration and hybridization experiments with some species of Hieracia. Botanisk Tidsskrift 27:225–248
Ostenfeld, C.H. On the immigration of Biddulphia sinensis Grev. and its occurrence in the North Sea during 1903-1907 and on its use for the study of the direction and rate of flow of the currents. Meddelelser fra Kommissionen for Danmarks Fiskeri- og Havundersøgelser: Serie Plankton 1 : 1-44.
Ostenfeld, C.H. & C.G. Johannes Petersen On the Ecology and Distribution of the Grass-Wrack in Danish Waters. Copenhagen, Centraltrykkeriet, 62 p. Series: The Danish Biological Station vol. 16.
Ostenfeld CH Further studies on the apogamy and hybridization of the Hieracia. Zeitschrif ind Abst und Vererb 3:241–285
*I : List of diatoms and flagellates / by C.H. Ostenfeld. 1910
*II : Protozoa / by C.H. Ostenfeld. 1910
*III : Peridiniales / by Ove Paulsen. 1910
*IV : General remarks on the microplankton / by C.H. Ostenfeld and Ove Paulsen. 1911
Ostenfeld, C. H. Plants collected during the First Thule Expedition to the northernmost Greenland. Meddelelser om Grønland, 51
*
Ostenfeld, C. E. H. Contributions to West Australian Botany, part I: Introduction, The sea-grasses of West Australia. Dansk Botanisk Arkiv, 2: 1-44
Ostenfeld, C. E. H. Contributions to West Australian Botany, part II: Stray notes from the tropical West Australia. Dansk Botanisk Arkiv, 2 : 1-29
Ostenfeld, C. E. H. Contributions to West Australian Botany, part II: A revision of the West Australian species of Triglochin, Crassula and Frankenia. Dansk Botanisk Arkiv, 2 : 30-55
Ostenfeld, C. E. H. Contributions to West Australian Botany, part III : Additions and notes to the flora of extra-tropical W. Australia. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab, 3: 1-144
Ostenfeld, C. H. Critical Notes on the Taxonomy and Nomenclature of Some Flowering Plants from Northern Greenland. Meddelelser om Grønland, 64
Ostenfeld, C. H. Flowering Plants and Ferns from Wolstenholme Sound and Two Plant Lists from Inglefield Gulf and Inglefield Land . Meddelelser om Grønland, 64: 189-206
Ostenfeld, C. H. The Vegetation of the North-Coast of Greenland. Based upon the late Dr. Th. Wulff's collections and observations. Meddelelser om Grønland, 64: 221-268
*
Ostenfeld, C.H. The flora of Greenland and its origin. Biologiske Meddelelser, Kongelige Danske Videnskabernes Selskab, 6, 1-71
Ostenfeld, C.H. The distribution within Denmark of the higher plants Results of the topographic-botanical investigation. 1: A brief historical survey of the investigation. Det Kongelige Danske Videnskabernes Selskabs Skrifter, Naturvidenskabelig og Mathematisk Afd., 9. Række, 3