90 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vol. 8, No. 2 



within Venezuela but for the most part recorded as from British Guiana. He has 

 pointed out that as delimited by natural watershed and boundary commission find- 

 ings, more than five-eighths, the western and southern portion of the summit (and 

 that part traversed by various expeditions) is Venezuelan, less than one- fourth, 

 the northeastern part (which is designated largely "inaccessible" on the Commis- 

 sion map), is British Guianan, and a very small portion, about one-eighth, on the 

 southeastern portion Brazilian, 



Further botanical exploration of the Guayana Highland has been made without 

 confusion of geography. 



For more than the past two decades the colleagues of Professor Henri Pittier, 

 namely Captain Felix Cardona, Doctors Tobias Lasser, Francisco Tamayo, and 

 others, have visited the Gran Sabana. The major collections of all of them are in 

 the Venezuelan National Herbarium. 



Over the period October 1, 1928 to March 18, 1929, the Sidney F. Tyler-Ameri- 

 can Museum of Natural History Fxpedition was led by Dr. Tate 7 in the first ascent 

 of Cerro Duida, on the western margin of the Guayana Highland. Tate's important 

 collections were deposited at the New York Botanical Garden, and became the 

 basis of the voluminous and important "Botanical results of the Tyler-Duida Ex- 

 pedition" by Gleason. 8 



Stimulated by the explorations of Roraima and Duida, The American Museum 

 of Natural History, the American Geographical Society, and the New York Botan- 

 ical Garden completed preliminary organization of an ambitious plan for the further 

 over-all biological, geological, and geographical survey of the Guayana Highland. 

 An outline entitled "Prospectus of the Pacaraima-Venezuela Expedition" was 

 issued, detailing proposed objectives for the cooperative undertaking. Unfortu- 

 nately, these well-balanced plans did not reach fruition. The American Museum 

 was, however, able independently to carry out a comparable exploration under the 

 sponsorship of Dr. William H. Phelps of Caracas. 



Tate 9 led the important William H. Phelps-American Museum of Natural History 

 Expedition of Auyan-tepui, near the Rio Carom in the northeastern part of the Gran 

 Sabana. Tate's invaluable plant collections from the region for the third time came 

 to the New York Botanical Garden. Report on them was made by Gleason and 

 Killip. 10 



In the meanwhile, George S. Jenman, from 1903 to 1929 Government Botanist 

 and Superintendent of the Botanic Garden, Georgetown, conducted extensive ex- 

 ploration in British Guiana and collected on the Kaieteur Escarpment about 

 Kaieteur Falls, on the Potaro River, which Im Thurn had visited in 1884. R. A. 

 Alston, who was Assistant Government Botanist and Mycologist in British Guiana 

 during 1923-1927, made two excursions into eastern Guayana. During August and 

 September of 1925, he collected at Macreba Falls on the Kurupung River, where it 

 drops from the sandstone plateau, and on the plateau itself along the Membaru 

 trail. Collections made here represent some 130 numbers. In March, April, and May 

 of 1926 Alston made an expedition up the Potaro River across the Kaieteur Pla- 

 teau to the Ireng River. This trip netted about 98 collections. Both are chiefly 

 deposited in the Jenman Herbarium, Georgetown, and at Kew. H. A. Gleason made 

 numerous important collections in the Potaro River Gorge in 1924. (Maguire vis- 

 ited the magnificent Kaieteur Falls and exciting Kaieteur Escarpment as a stu- 

 dent of zoology in 19250 



7 Tate, G. H. H. & Hitchcock, C. B. Geogr. Rev. 20: 31-52. 1930. 

 "Bull. Torrey Club 58: 277-506. 1931. 

 9 Geogr. Rev. 28: 452-473. 1938. 

 10 Brittonia 3: 141-204. 1939. 



