198 aceraceyE. 



eastward and northward to Pennsylvania and Michigan, and westward to the 

 southern part of the Rocky Mountains), a second to CaUfornia, and the third 

 to the interior of Mexico. Recently the lamented Zuccarini has brought to 

 light a fourth species indigenous to Japan, furnishing an additional illustra- 

 tion of the close analogy which exists between the vegetation of that country 

 and that of the United States. 



The larger Maples are fine timber-trees in their native forests, especially 

 A. saccharinum, and are planted as favorite shade-trees. The limpid ascend- 

 ing vernal sap, perhaps of all the species, contains sugar, which is largely 

 obtained by boiling from our well-known Sugar Maple, and to some extent 

 from our White Maple. The Negundo also yields sugar. The proper 

 elaborated juices of these trees become somewhat bitter and acrid as the veg- 

 etation advances, and in a few European species they are lactescent. The 

 bark possesses some astringency ; that of some European species is said to 

 furnish the dyer reddish-brown and yellow colors. 



The development of the ovules, and the mode in which they are attached 

 to the placenta by nearly their whole inner face, is admirably illustrated by 

 Adrien de Jussieu, in his Monographie des Malpighiacees, p. 137, plate 1, 

 fig. 12 - 14. By the growth of the upper part of the ovule after fertilization, 

 the seed becomes anatropous. 



The mode in which the embryo of the Maples is folded or enrolled 

 varies in diflferent species, and will probably coincide with the marked dif- 

 ferences in the inflorescence and flowers, so as to give characters to the 

 sections of the genus. The cotyledons are more commonly incumbent than 

 accumbent. 



