10 



which have heen collected in Danish waters hy others in earlier and more re- 

 cent times. 



Other collections. Lvngbye's herbarium of Algae, kept in the Botanical Mu- 

 seum of Copenhagen , is of the greatest importance for the study of the Danish 

 marine Algai, as it contains the original specimens of Lynch yk's Hydrophytology. 

 The specimens in this herbarium have not been particularly well prepared, but 

 they are furnished with exact indications of the place and time of collecting ; most 

 of them originate from the neighbourhood of Hofmansgave on Fyen. 



The Botanical Museum's Danish herbarium contains a considerable number 

 of specimens of marine Algae. The majority of these come however, like Lyngbye's 

 herbarium, from the neighbourhood of Hofmansgave and have been collected mainly 

 by HoFMAN Bang and Miss Caroline Rosenherg. The latter, who passed the greater 

 part of her life (f 1902) at Hofmansgave, has from there during a long series of 

 years sent a large number of carefully prepared specimens of marine Alga? , many 

 of which have come to be housed in the Botanical Museum's herbarium. As they 

 have been collected at different seasons, they provide a good matei-ial for following 

 the development of the single species during the course of the year. Further, spe- 

 cimens are also present from Hounemann, Liebman and 0hsted, by which the 

 determinations of the latter can be controlled, and also from J.Vahl, CM. Poulsen, 

 Job. Lange, Chh. Thomsen (mostly from Samso), J. P. Jacobsen (mostly from the 

 I^imfjord), E. Rostrup, C. Rasch and others. 



Since I began my systematic collections, some material collected by others 

 has further been left to me. Dr. Th. Mortensen has thus placed at my disposal 

 a valuable collection principally from the Limfjord procured at different seasons 

 in 1894 — 95; and Dr. F. Borgesen has permitted me to examine the Algae dredged 

 on two expeditions with the fisherj'-inspection ship S. S. "Guldborgsund" in 1897 

 and in 1898 in the Skagerak, Kattegat and the Baltic. Smaller collections have 

 been given me^by Dr. C. H. Ostenfeld, Mr. A. Otterstrom, Mag. Ove Paulsen 

 and Mag. Hennlng E. Petersen. 



My own collections. I began my first collections of Danish marine Algae 

 already ^towards the end of the seventies, but it was not until 1890 that I made 

 extensive and systematic collections and they were carried on most energetically 

 during the years 1891 — 1895, whilst later they have been continued almost every 

 year though less extensively. My aim has been to make as uniform an investi- 

 gation of the Danish waters as possible and also, as far as possible, to investigate 

 them at different seasons; for that purpose I have made dredgings at more than 

 700 different places and besides made collections at numerous harbours and at 

 other places close to the land; I have made these collections during all the months 

 of the year, chiefly however during May— September. The dredgings have almost all 

 been made by^^means of a triangular dredge with sharp steel teeth (Reinke's model), 

 more rarely with a quadrangular dredge without teeth or with seine. The greater 

 part of the material has been preserved as herbarium specimens, of which I possess 



