2')!) Allgemeines. — Anatomie. 



In the Colorado desert of California they found various types of 

 soil conditions, the gravel hüls, the alkali flats, and the salt plains. 

 Neowashingtonia filifera grows on the parched eastern slopes of the 

 San Bernardino mountains in miniature oases formed by the out- 

 cropping of clay soil, out of which the water collected on the hüls filters. 

 The Mohave desert was also visited, and leastly the grand canyon of 

 the Colorado river. In the last named place the absence of plants, 

 which might well have spread from the Mohave region, was noticed 

 and ascribed to the probable peculiar climatic conditions which no doubt 

 exist in the very narrow canyon. 



Following this account of the actual journey is a consideration of 

 the characteristics of deserts in general and North American deserts 

 in particular. Meteorological tables, showing the rainfall at various 

 points are given, and the character of the soüs as factors in desert for- 

 mation are discussed. An historical account of the desert regions 

 of America shows that the idea of the „Great American Desert" 

 at it is figured by older cartographers, is incorrect. The deserts 

 of North America may be designated as the Sonora-Nevada 

 desert, comprising portions of Utah, Idaho, Washington, 

 Oregon, Nevada, California, Arizona, Baja California, 

 Sonora, and Sinai oa; and the Chihuahua desert, which occupies 

 the table land of Mexico east of the Sierra Madre, running north 

 into Texas, Arizona, and New Mexico. Still further north the 

 desert lands in the Dakotas in Wyoming and Montana might, it 

 is stated, be regarded as the northern arm of the Chihuahua region, 

 from the Standpoint of this paper. At the close is a discussion of the 

 results of experiments performed at an earlier date in the lava desert 

 region of Arizona, by Dr. MacDougal. A comparison of two desert 

 plants, Mentzelia pumila and Artemisia sp., with two moisture loving 

 fonns, tomato and Eucalyptus globulus, experimented with elsewhere, 

 shows an enormous disparity in the rate of transpiration. As to tempe- 

 rature it was found that the plant-body of an Opuntia attained a height 

 of 111,2" Fahr., while in Cereus temperatures of 113° — 115° Fahr, were 

 often found. The fact that this is above the critical temperature usually 

 given for Chlorophyll leads to the Suggestion given, that the protoplasm 

 and chloroplasts must have undergone especial adaptations to such con- 

 ditions, although it is not unlikely that the death of plants in such 

 regions is often the result of excessive insolation. 



A bibliography by W. A. Cannon, at present resident investigator 

 at the laboratory, is appended, and the article is very fully ülustrated 

 by numerous füll page plates, showing the characteristic regions and 

 also individual plants, considered in the text. 



H. M. Richards (New-York). 



KUPFER, E. M., Anatomy and Physiology of Baccharis 

 genistelloides. (Bull. Torrey Bot. Club. Vol. XXX. p. 685 

 —696. fig. 1 — 11 in text. Dec. 1903.) 



Finds that the plant is well adapted to conditions of dryness and 

 great insolation, owing to the Ioss of the leaves, and the development 

 of the wings of the stem which are provided with coverings of cutin, 

 wax, and hairs. The glandulär hairs contain Chlorophyll. The stereome 

 tissue is early lignified, giving the characteristic rigidity to the plant. 

 The wings are to be regarded as lateral-vertical expansions of the stem 

 and not as decurrent leaves. The leaves differ from the wings in sho- 

 wing a marked dorsiventrality. The shoots are apogeotropic and posi- 

 tively phototropic. From cuttings, plants were produced, which bore 

 reversionary leaves and greatly reduced wings. 



H. M. Richards (New-York). 



