ENTOMOLOGIST AND BOTANIST. 



249 



THE OAKS. 



Tlie genus Quercus, which embraces the Oaks, 

 is very widely diffused over the countries of 

 the Northern Hemisphere. Different countries 

 vary mucli iu the number of species which tliey 

 produce. Thus, in the British islands, there 

 are but two species ; one with sessile or stalkless 

 acorns (Quercus sessiliflora, Salisb.), and the 

 other with acorns on a stem or peduncle {Q. 

 jiedunculata, L.) Indeed, these two forms have 

 by some botanists been considered as but varie- 

 ties of one species (Quercus robur). 



The countries of Northern Eui'ope are mainly 

 limited to these two forms, but in France, Spain, 

 and the Mediterranean States, several other 

 species are introduced. New species occur 

 again iu Asia Minor, Ivoordistan, the Himal- 

 ayas, Eastern Asia, and the Indian islands, so 

 that some two hundred species have been de- 

 scribed in different parts of the world. 



The North American Oaks are a very intei-- 

 esting group, and include a large number of 

 species, each having a more or less extensive 

 range. In the district east of the Rocky Moun- 

 tains we have about twenty species ; new ones 

 occur in Texas, Mexico and California. 



The different kinds of Oaks manifest a dispo- 

 sition to hybridize quite freely, so that wc fre- 

 ((uently meet with intermediate forms which 

 arc quite puzzling. 



■\Ve propose to give, in a series of articles, an 

 account of the Oaks of this country, illustrated 

 iu most cases by such figures as may help our 

 readers to a determination of the various kinds 

 they may meet with. 



The principal characters of the genus are 

 mainly as follows: Trees or shrubs, with alter- 

 nate leaves, and with sterile aud fertile flowers 

 separate; the sterile ones on slender, thread- 

 like, drooping stems; the fertile ones small and 

 inconspicuous, consisting of a three-celled ovary, 

 enclosed by a scaly covering, which when en- 

 larged becomes a kind of cup to contain the 

 fruit or acorn. Although ths ovary is at first 

 three-celled, with two ovules in each cell, yet 

 bjt one of the ovules is fertile, and that enlarges 

 to fill the whole cavity. 



All our species of Oaks are divided into two 

 sections, distinguished by the time occupied in 

 the full development of the fruit, viz: first, those 

 which mature the fruit iu one season ; and sec- 

 ond, those whose fruit is two years in acquiring 

 maturity. The first section includes the White 

 and Chestnut Oaks, also the Live Oak of the 

 Southern States. Of these the leaves usually 

 have blunt lobes, aud the acorns are sweet or 



sweetish, and some of them edible. In this 

 section the acorns are produced on the new 

 twigs, and are generally more or less stalked. 

 In the second section the leaves are either entire, 

 or lobed and bristle-pointed; the acorns are 

 bitter, and are matured on the twigs of the last 

 season, and below the new shoots. This sec- 

 tion includes the Red and Black Oaks, the 

 Spanish and Pin Oaks, aud the Willow-leaved 

 Oaks. 



We present in this number the White, Bur, 

 and Post Oaks, belonging to the first section. 



[Fig. 150,1 



White Oak— (Qkcitus alba, L.) 



The White Oak is one of our largest aud most 

 valuable forest trees. It is found in almost all 

 the wooded portions of the country, particularly 

 on uplands and hills. Its wood is compact, 

 white, strong and durable. The bark of young 

 trees is smooth and whitish, on old trees it is 

 somewhat furrowed and roughened, but still of 

 a light ash color. The leaves present consider- 

 able diversity both in outline and in the number 

 and depth of the side lobes. They are usually 

 oblong, when mature five or six inches long, 

 and more than half as wide ; with from three 

 to six oblong, obtuse lobes on each side, the 

 middle ones longest, the divisions extending 

 sometimes half way, aud sometimes nearly to 



