i894. NOTES AND COMMENTS. 409 



Death Valley. 

 Under the title " Botany of the Death Valley Expedition," the 

 U.S. Department of Agriculture have recently issued a bulky report, 

 prepared by Mr. F. V. Coville, botanist to the expedition, and now head 

 of the division of Botany. Death Valley, bounded on the east by 

 the Funeral Mountains and westward by the Panamints, lies on 

 the Nevada side of California, and forms part of the vast more 

 or less desert region broken by short mountain ranges, which extends 

 between the Rocky Mountains and the Sierra Nevada. In and 

 about this cheerful region, Mr. Coville and his assistants spent more 

 than six months of 1891, collecting plants and making observations on 

 their habitat and environment. An idea of the nature of the country 

 may be gathered from the following description: — "January 19 we 

 broke camp, and set out for Death Valley by the old borax road. 

 The excessive dryness of the region was evidenced by the fact that 

 the pencil marks on a roadside grave-board, which had been twelve 

 years exposed to atmospheric effects, still appeared clear and fresh, 

 the surface of the wood retaining its natural appearance. We passed 

 the night in Long Valley, and in the morning continued down the 

 caiion, emerging into Death Valley near the south end of its alkali- 

 ilat. On either side were high mountains and between them the 

 narrow valley, not more than ten miles wide. In the bottom of the 

 valley was the snow-white stretch of salt and alkali, and to the north- 

 ward, perhaps fifty miles away, mountains, valleys, and salt-flat 

 vanished in haze. Creosote bush had been characteristic of all our 

 route until we neared the salt-flat ; but here, under the influence of 

 clay and alkali, it gave way to greasewood [Atriplex polycarpa), that in 

 turn to salt grass [Distichlis spicata), and the last to a shrub related to 

 the pickle-weed." Beyond this there was no vegetation whatever. 



The report, which occupies nearly 300 pages, is an example of 

 what such reports should be, and an illustration of what can be done 

 by a collector who is at the same time a proficient botanist. Besides 

 an exhaustive catalogue of species, including descriptions of 42 

 novelties, and a tabulated list of specimens arranged in the order of 

 collecting numbers, with date of collection, locality, and altitude, the 

 author gives a valuable account of the distribution of plants in 

 South-eastern California, and of the relationships of the mountain 

 flora of the Sierra Nevada, and of that of Death Valley, and also 

 discusses at some length the characteristics and adaptations of the 

 desert flora. In a humid climate dew is an important source of 

 moisture, but the weather-observer recorded no dew in Death Valley, 

 and the several months' observations of desert conditions and 

 phenomena have led to the conclusion that a very important pro- 

 portion, perhaps in some cases all, of the summer water-supply of 

 certain desert-shrubs is conserved in the soil as capillary moisture 

 derived from local rainfall. The tree Yucca [Y. arhorescens) is the 

 nearest approach to the real tree that the desert affords, often attain- 



