504 BOTANICAL GAZETTE [JUNE 
solutions. With increasing concentrations of glucose (4-14 per cent), mannite 
(4-14 per cent), and Hellriegel’s nutrient solution, there is a corresponding 
retardation of growth and increase of alcohol production. Low or high tem- 
peratures which retard growth also favor alcohol production, while at inter- 
under conditions of complete aeration, and correlates alcohol production with 
retardation of growth. It is immaterial whether the retardation of growth is 
rought about by unfavorable temperatures, high osmotic pressures, or other 
factors.—H. HASSELBRING. 
Vegetation about Tucson, Arizona.—SHREVE” has compiled an excellent 
brief but comprehensive guide to the features of ecological interest in the 
vicinity of Tucson, Arizona. In addition to the better known desert and semi- 
desert areas immediately surrounding the city, he has included the more diver- 
sified conditions found in the adjacent Santa Catalina mountains. Starting 
Echinocactus, and Fouquieria splendens are conspicuous, the desert forms are 
found to disappear with increasing altitude, grasses and shrubs becoming more 
abundant, until at 1550 meters upon the north-facing slopes there is an open 
forest of such species as Juniperus pachyphloea, Quercus oblongifolia, Q. Emoryi, 
Arctostaphylos pungens, Rhus trilobata, and other woody forms. further 
ascent of some 500 meters reveals forests of Pinus arizonica and smaller stands 
of other pines and oaks, with specimens of Arbutus arizonica. Finally, at 
2350 meters this interesting succession finds its climax upon slopes forested 
with Pseudotsuga, Abies concolor, and Pinus strobiformis, with even more 
mesophytic forms along the water courses and in the undergrowth. A brief 
analysis is also presented of the factors which cause this diversity of vegetation. 
—Geo. D. FULLER 
Water reaction in a liverwort—CANNON® reports experiments with a 
species of Plagiochasma found upon arid slopes of the Santa Catalina moun- 
tains, Arizona, at an altitude of 5000 feet, showing that the thalli are able to 
become air dry, involving the loss of over 70 per cent of their original weight; but 
upon being given water again they continued to grow without apparent injury. 
He has also demonstrated that these plants may endure such a desiccated con- 
dition for at least 25 days, and upon their restoration to moist conditions at 
once assume active growth. These experiments show clearly that this liver- 
wort can withstand in nature conditions of extreme aridity.—Gro. D. FULLER. 
* SHREVE, Forrest, A guide to the salient physical and vegetational features 
of the vicinity of Tucson, Ariz. International Phytogeographic Excursion in Amer. 
PP. II. 1913. 
Cannon, W. A., A note on the ahigaes of the water reaction of a desert 
liverwort. Plant World 17:261-265. 1 
