APPENDIX. 



During the progress of our investigations much information has been received from 

 numerous sources which could not be included in publication at the logical places. Some 

 of this was taken up in the appendix to the first volume (Cactaceae i : 216-225) and some 

 in the appendix to the second (Cactaceae 2: 223-226); what remains is included in this 

 appendix to the whole work. 



Dr. David Griffiths, who studied the species of Opuntia, especially with relation to 

 their economic possibilities, and grew many of them at experimental stations of the United 

 States Department of Agriculture at Brownsville, Texas, and at Chico, California, has 

 published and described many species as new. We have included these in our studies of 

 the genus and have grouped them with the species known to us as accurately as has been 

 possible from his published descriptions and illustrations and after examination of as 

 many of his type specimens as we have been permitted to see; however, conditions were 

 such that we have not been able to study a number of them. They have not been arranged 

 for ready reference by students. 



The preface to Volume I gives a list of volunteers who have made valuable con- 

 tributions of specimens and data to this investigation. Many of these have continued to 

 aid us. 



Dr. Britton, in continuing his West Indian studies, investigated the cacti of Grenada 

 and of Trinidad in 1920 and 1921 and published an account of the Trinidad species. 



Dr. John K. Small has continued his investigation of the southeastern United States 

 and of Florida in particular, in cooperation with Mr. Charles Deering, and has greatly 

 increased our knowledge of the cacti existing there, including the discovery of many 

 undescribed species of Opuntia. 



Dr. Francis W. Pennell, Curator of Botany at the Academy of Natural Sciences of 

 Philadelphia, and Mr. E- P. Killip, of the United States National Museum, made extensive 

 botanical collections in Colombia in 1922, including some specimens of cacti, which we 

 have studied. 



Dr. Henry H. Rusby led the Mulford Biological Exploring Expedition to Bolivia in 

 192 1 -1 92 2 and with the assistance of Dr. O. E. White obtained for us specimens of several 

 little-known cacti. 



Dr. Philip A. Munz has sent us cacti from the deserts of southern California. 



Mr. C. Z. Nelson obtained cacti from southern Mexico, including a beautiful new 

 species of Selenicereus. 



Mr. Francis J. Dyer, while connected with the Consular Service in Honduras and 

 at Nogales, Mexico, sent us many specimens from those stations. 



Professor Harvey M. Hall, while making extensive explorations in the western United 

 States in connection with his own work, has forwarded interesting cactus plants. 



Dr. and Mrs. Charles D. Walcott have sent specimens from Alberta, Canada, some of 

 them coming from near the most northern range of the family. 



Dr. W. L. Abbott and Mr. E- C. Leonard made extensive collections in Haiti in 1920 

 and obtained a number of rare and little-known plants, including one which had been 

 collected by Charles Plumier about 1698 and which proved to be a new genus; this was 

 named by us for Dr. Abbott. More recently Dr. Abbott has sent us specimens from 

 Santo Domingo. 



Dr. George F. Gaumer, the veteran collector in Yucatan, has sent very important 

 collections from his region, including a number of new species. 



Mr. Ivan M. Johnston, who accompanied the scientific expedition sent out by the 

 California Academy of Sciences in 1921 to explore the islands of the Gulf of California, 



