88 NOTICES OF BOOKS 



high) is placed in the Pilocereus section, but having the seed of a true 

 Cereus, thus reuniting the two genera. 



At p. 54 the author candidly acknowledges that, owing often to im- 

 perfect materials and dried specimens, he may have increased the 

 number of species more than he would probably have done had he 

 perfect specimens and living plants before him : thus, for example, that 

 the 30 Mamillaria might be reduced to 22 ; 20 Echinocacti, to 15 ; 31 

 Cerei, to 18 ; and 50 Opuntice, to 31. The concluding pages of the 

 Memoir are devoted to some remarks on the geographical distribution 

 of the Cactacece in the territory of the United States : showing that the 

 Atlantic region has only oue single species, Opimtia (along the southern 

 coast some West Indian species may be expected) ; the Mississippi re- 

 gion, 2 Mamillaries and 3 Opuntice ; the Texan region, 5 Mamillaries , 3 

 EcJdnocacti, 6 Cerei, and 6 Opuntice ; the New Mexican region, the 

 richest of all, yields 19 Mamillaries, 9 Echinocacti, 16 Cerei, and 22 

 Opuntice ; the Gila region has 5 Mamillaries, 6 Echinocacti, 7 Cerei, and 

 18 Opuntice; the Californian region has 1 Mamillaria, 1 Echinocactus, 

 1 Cereus, and 3 Opuntice ; and, lastly, the North- Western region has, 

 like the Atlantic, only one species, an Opimtia, common also to the 

 Missouri, but quite different from the Eastern species, 0. vulgaris* 



Witterung unci Wachsthum, oder Grundzuge der Pflanzenkli- 

 matologie; von Herman Hoffmann, Doctor der Medecin und 

 Philosophic, ordentl. Professor der Botanik in Giessen. Leipzig, 



1857. 



Under the above title, which may be paraphrased (for, like so many 

 German titles, it hardly admits of translation into English), " Climate 

 and Growth, or the Elements of Climatology as it affects Plants," 

 we have a laborious work by Dr. Hoffmann, Professor of Botany at 

 Giessen. In the fifth volume of this Journal, page 408, we had occa- 

 sion to allude favourably to Dr. Hoffmann's pamphlet on the areas of 

 distribution of the Phamogamous plants of North Germany, and from 

 the present work we may judge that his attention has since then been 

 turned to another branch of the same great subject of the causes of 

 distribution. 



The volume now before us is a substantial octavo of nearly 600 



