118 



ized and modified flowers, which gradually fitted their forms and 

 the position of their honey-glands to the forms of the bees or but- 

 terflies, showed a natural tendency to pass from yellow through pink 

 and red to purple and blue, it would follow that the insects which 

 were being evolved side by side with them, and which were aiding 

 at the same time in their evolution, would grow to recognize these 

 developed colors as the visible symbols of those flowers from which 

 they could obtain the largest amount of honey with the least possi- 

 ble trouble. Thus it would finally result that the ordinary unspec- 

 ialized flowers, which depended upon small insect riff-raff, would 

 be mostly left yellow or white ; those which appealed to rather 

 higher insects would become pink or red; and those which laid 

 themselves out for bees and butterflies would grow for the most 

 part to be purple or blue. Now, this is very much what we actually 

 find to be the case in nature. 



The Variability of Oaks, — In some remarks upon a note by 

 Mr. Meehan, on * Hybrid Oaks,' which appeared on page 55 of the 

 Bulletin, M, DeCandolle {Arch, des Sci. Fhys, et A^a/.^p. 557) says 

 that it is interesting to find that in a Qiterciis robur raised in America, 

 a country to which the species is not indigenous, and one in which 

 no allied form exists to cross with it, the same mixture of forms has 

 been observed that he called attention to in 1862, when he reduced 

 the so called species Q. pedunculata and Q, sessiliflora to Q. robur. 

 M. DeCandolle remarks that *' many similar facts have been noted 

 in annual or perennial plants introduced into cultivation, and no 

 one, it seems to me, can doubt that variations sometimes occur with- 

 out hybridization." 



Botanical Literature, 



Sylloge Fimgorum omnium hucusque cognitorum. By Prof, P. A. Sac- 



^cardo. Large 8vo., pp. 768. Padua, Italy. 



The first volume of this long-expected work has at length ap- 

 peared, and will help to fill a want long felt by all students of. my- 

 cology. It forms a large octavo of 768 pages, with descriptions of 

 about 2,900 species of Sphaeriaceous Fungi. Adding much to the 

 practical value of the work are the habitat lists, giving in alphabetical 

 order the names of the trees and plants on which the different spe- 

 cies grow. The volume is published at 49 francs, which, consider- 

 ing the labor of preparing such a work, is very reasonable. It is 

 to be hoped that the demand for this first volume may be such as 



to encourage the author to go on with the compilation of the remain- 

 ing orders. — J. B. E. 



Books and Pamphlets Received. 



Index to the Genus Carex of Grafs Manual. By Jos. F. James. 

 8vo., pamph., pp. n, (Reprint from the Botanical Gazetted 



From the author. 



f Iowa, Nos. iv. and v. By J 



Darwin 



8yo., pamph., pp. 4 and 5. (Extracts from Proceedings of the 

 Davenport Acad. Sci.) From the author. 



