4 THE CACTACEAE. 



Early in 191 2 Dr. Rose went to Europe to study the collections there and to 

 arrange for exchanges with various botanical institutions having collections of these 

 plants. He spent considerable time at London, mainly at the Royal Botanic 

 Gardens, Kew, where through the courtesy of the Director, Sir David Prain, he was 

 able to examine the greenhouse, illustrative, and herbarium material for which this 

 institution has long been famed. The collection at the British Museum of Natural 

 History and that of the Linnaean Society of London were examined. At Paris he 

 studied the collections at the Natural History Museum, many of which have historic 

 interest; one of his interesting discoveries there was that the Pereskia bleo, collected 

 by Baron Friedrich Alexander von Humboldt in Colombia, is a very different species 

 from the plant which for nearly a century has been passing in our collections and 

 literature under that name. He also visited the famous botanical garden of the 

 late Sir Thomas Hanbury, at La Mortola, Italy, and through the courtesy of Lady 

 Hanbury was given every possible facility for the study of this collection; Mr. 

 Alwin Berger, who was then curator in charge, had brought together one of the most 

 extensive representations of this family to be found growing in the open in any 

 place in the world. Here in the delightful climate of the Riviera were grown many 

 species which were apparently just as much at home as they would have been in 

 their desert habitats. Dr. Rose also visited Rome, Naples, Venice, and Florence, 

 where he saw smaller collections in parks and private gardens. At Munich he 

 examined certain types in the Royal Botanical Museum, then under the charge of 

 Dr. L. Radlkofer, and saw some interesting species in the Royal Botanical Garden 

 then being organized by Dr. K. Goebel. At Berlin he examined the herbarium and 

 living specimens in the Berlin Botanical Garden, through the courtesy of Dr. A. 

 Engler, and the West Indian collection through the courtesy of Dr. I. Urban. He 

 then went to Halle and saw L. Ouehl's collection of mammiUarias; to Erfurt, where 

 he saw the Haage and Schmidt, and Haage Jr. collections; to Darmstadt to see the 

 Botanical Garden under Dr. J. A. Purpus; and to Antwerp to see DeLaet's private 

 collection. 



In 19 13 Dr. Britton and Dr. Rose visited the West Indies. Dr. Britton, who 

 was accompanied by Mrs. E- G. Britton, Miss D. W. Marble, and Dr. J. A. Shafer, 

 collected on St. Thomas and the other Virgin Islands, Porto Rico, and Curasao. 

 At the latter island he rediscovered the very rare Cactus mammiUarls, which had not 

 been in cultivation for many years. Dr. Rose, who was accompanied by WiUiam 

 R. Fitch and Paul G. Russell, also stopped at St. Thomas, and collected on St. 

 Croix, St. Christopher, Antigua, and Santo Domingo. 



In 19 14 and 19 15 Dr. Britton again visited Porto Rico and, assisted by Mr. 

 John F. Cowell and Mr. Stewardson Brown, explored the entire southwestern arid 

 coast and the small islands Desecheo, Mona, and Muertos. 



In 1 9 14 Dr. Rose went to the west coast of South America, making short stops 

 at Jamaica and Panama. He made extensive collections in central and southern 

 Peru, central Bolivia, and northern and central Chile. At Santiago, Chile, he 

 examined a number of Philippi's types in the National Museum and obtained 

 some rare specimens from the Botanical Garden through the courtesy of Johannes 

 Sohrens. 



