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SCIENCE. 



[N. S. Vol. XX. No. 499. 



palmettos and often occupy isolated area^ 

 entirely surrounded by pine forests as in 

 southern Florida; characteristic trees of these 

 hammocks are Dipholis salicifolia, Eugenia 

 confiisa,, Icacorea paniculata and Gocolohis 

 laurifolia, all of which occur in similar situa- 

 tions in Florida. 



Dr. C. F. Millspaug'h, who was with Dr. 

 Britton and remained somewhat longer, was 

 asked to discuss the paper. He reported that 

 plants found in bloom at the center of the 

 island were found in fruit at the west end, 

 while at the east end, which is dry and rocky, 

 the buds of the same species were scarcely 

 started. South Bemini is much like New 

 Providence in vegetation, though its elevation 

 is less. A Rhus resembling jB. toxicodendron 

 was found on Cat Cay and there is an inter- 

 esting palm on the same island. 



Inquiry was made concerning Groton Elu- 

 teria, which is prized in West Indian countries 

 as a bitter drug, but is said to be disappearing. 

 The plant had not been seen, but a guide said 

 that it grew on South Bemini. 



Professor Underwood called attention to 

 Odontosoria clavata, which in Jamaica and 

 Cuba grows in very wet places and is a soft 

 tender plant, while in the Bahamas what is 

 apparently the same species grows in dry pot- 

 holes and is firmer and stronger. 



The second paper was by Dr. D. T. Mac- 

 Dougal on ' Desert and Delta Vegetation of 

 Sonora and Baja, California.' The Colorado 

 Elver has been called the Nile of America. 

 It flows 600 miles without tributaries and has 

 a delta 150 to 200 miles long by 50 to 100 

 miles broad. In this region is the most pro- 

 nounced desert in the United States and prob- 

 ably in America. The topography of the 

 region may be described as a great basin with 

 the Colorado River flowing along the eastern 

 margin. The Salton basin is 400 feet below 

 sea level and in times of unusual flood is trans- 

 formed into a great lake by overflow of the 

 Colorado River, the last such flood occurring 

 in 1891, when part of the track of the Southern 

 Pacific Railroad was under water. At one 

 point in this basin there has been an elevation 

 of mud volcanoes from ten- to fifty feet high, 

 where there are hot sulphur springs. The dry 



season is from August to April or May. At 

 the end of the wet season the Indians dig 

 holes deep enough to get into and plant their 

 corn and melons in these. The surface of 

 the ground becomes very dry, but enough 

 moisture is retained to mature the crops. 

 Within a few yards of the river channels 

 relative humidities of eleven, twelve or thirteen 

 per cent, were observed. The temperature of 

 the summer flood water is 45° to 55°, while the 

 air temperatures are the highest to be found 

 in the country, 100° to 125°. At the lower 

 end of the delta is a region of brackish water. 



Distichlis spicata is widely distributed on 

 the mud flats; the Mexican poplar, an uniden- 

 tified willow and the mesquite were the trees 

 observed, while the arrow-weed forms almost 

 impenetrable thickets. Within the width of 

 a few yards one passes from river vegetation 

 to true desert. 



Ammohroma Sonoroe, described by Torrey, 

 has a stem two to four feet long, all buried 

 except the head. It is parasitic on Atriplex 

 roots. A puff ball with the same form and 

 similar appearance was found, but it was too 

 brittle to stand carrying. 



The east coast of Baja, California, near the 

 head of the Gulf, is supposed to be the driest 

 spot in America. One half inch of rain only 

 has been recorded at Yuma during 1903, and 

 Palmer visited an island in the gulf in 1889 

 which had no rain for a year and a half. 

 Landings were made at three points, the 

 farthest at San Felipe Bay, 55 miles below 

 the river. Mr. Brandegee visited San Luis 

 Bay once, but the San Felipe region was 

 entirely unexplored by botanists. Here the 

 coast rises by gradual slope to 500 feet 

 and then by precipitous rocks to peaks, 

 one of which is over 10,000 feet high. 

 The seasons are evidently irregular and not 

 clearly marked. Many of the plants have 

 milky or resinous juice and many are aro- 

 matic. Cereus Schottii was found forming 

 dense groves near San Felipe. Living plants 

 of what is probably Cereus Pecten-aboriginum 

 were brought home. The Indian-comb cactus 

 has a short trunk and long branches in con- 

 trast to the usual form of C. giganteus. 



Although the plants are very sparse it is not 



