374 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the protoplasm of plants is not prohibited from availing itself 

 of food such as that by which the protoplasm of animals is 

 nourished. 



REPORT ON THE PLANTS OF THE WILKES EXPLORING EXPE- 

 DITION. 



Among the gaps that have remained unfilled in the series 

 of reports of the Wilkes expedition has been that on the 

 plants collected by the party, partly in consequence of the 

 failure of Congress to make the necessary appropriations, 

 and partly on account of the death of Dr. Torrey, who had 

 charge of the phenogamous portion. This volume, however, 

 has lately appeared, Dr. Gray having undertaken the work 

 of Dr. Torrey after his death. That part relating to the 

 cryptogamous plants (consisting of the mosses) had been al- 

 ready published in several portions, as well as that on the 

 mosses as prepared by Mr.W. S. Sullivant, that of the lichens 

 by Professor Tuckerman, and that on the algae by Professors 

 Bailey and Harvey ; the fungi by the late Dr. Curtis and Mr. 

 Berkeley. 4 Z>, October, 1874, 3-22. 



VEGETATION IN THE SHEEP - RAISING PORTIONS OF SOUTH 



AFRICA. 



It appears from an article in the journal of the Linnaean 

 Society that the introduction of sheep into South Africa has 

 effected great changes in the vegetation of the sheep-raising 

 portion of that region. Besides the naturalization of the 

 cockle -burr (Xanthium spinosum), which has spread so ex- 

 tensively that only special laws and the rigid enforcement 

 of penalties have kept it from proving the ruin of the wool 

 producers, the native grasses have succumbed to close crop- 

 ping, and only shrubby plants remain as the chief resource 

 of the flocks. As a consequence, the rain-fall is said to have 

 become less certain, and to take more frequently the form of 

 thunder- torrents, and the perennial springs are every year 

 less copious. Favored by these changes, and protected by 

 their bitter or poisonous qualities from the sheep, several of 

 the more hardy plants of the adjoining half-desert region are 

 gradually encroaching upon the feeding-grounds, and in some 

 cases have taken possession of large districts. Jour. Linnce- 

 an Soc, XIV., 202-208. 



