114 



SMITHSONIAN INSTITUTION 



Swartz was in close touch also with the German botanist, Willdenow, 

 and in the beautifully preserved Willdenovian herbarium at the Berlin 

 Botanical Museum I found many of his duplicates, these agreeing 

 almost without exception with the Stockholm material so named. 

 Willdenow's own tropical American species were examined as care- 

 fully as time permitted, and the period of six days devoted to this 

 study and to examining fern material in the rich general herbarium at 

 Berlin proved all too brief. 



On the way to Germany I had the privilege of spending several 

 days at the Botanisk Museum, Copenhagen, with Dr. Carl Christensen, 

 leading world authority on Pteridophyta. and of discussing with him 



Fig. 99. — A small section of the exhibit of living Cacti. Botanischer Garten, 



Berlin-Dahlem. 



many prolilems of mutual concern in connection with our work upon 

 this group. Of particular interest were the types of numerous species 

 proposed long ago by Liebmann, from Mexico. 



Substantial progress in the Jamaican work was made during the 

 summer, and the trip was profitable in other ways. It was made pos- 

 sible through generous support extended by the American Association 

 for the Advancement of Science, the Smithsonian Institution, the 

 New York Botanical Garden, and the British Museum (Natural 

 History). The manuscript is to be published by the last institution. 



To the directors and curators of the institutions visited is oiTered 

 a very sincere expression of appreciation of assistance and innumer- 

 able courtesies extended. 



