280 



THE AMEEICAN 



of timber, following the water-courses, con- 

 verged to the great outlets, leaving many inter- 

 mediate spaces which would earliest be occupied 

 by the grasses and herbaceous, plants. The 

 beginning of these timber lines would naturally 

 be at the points of earliest drainage, i. e., near 

 the sources of the streams ; but a line of com- 

 munication having once been established to the 

 outlet, the seed distribution would also operate 

 up stream, whence it comes to pass that some 

 southern species have extended northward in 

 the bottoms of the larger rivers nearly or quite 

 through the extent of the prairie region, as the 

 papaw, the persimmon, and the Kentucky 

 coffee-tree. 



We do not offer this as a full solution of the 

 prairie question ; probably the annual burnings 

 by the Indians, and other influences not yet 

 understood, operated in the production of these 

 gardens of the West. 



One element to be taken into consideration in 

 the discussion of this subject is the peculiar 

 character of prairie vegetation. If it shall ap- 

 pear that there is a class of vegetation which 

 does not occur outside of the prairie region, we 

 must then bring in other influences tljan those 

 presented by the theory under consideration. 

 We will refer to some of the plants which are 

 usually regarded as of this character, viz : 

 lianunclus rhomboideics, Viola delphini folia, 

 Linum Bootii, Amorpha canescens, Baptisia 

 leucantha, Geuni trijlorum, Potentilla arguta, 

 JSryngium yucccBfoliuvi, JSulophus Americanus, 

 Solidago BiddelUi, Silphium laciniatum, Silph- 

 ium ierebinthaceum, Ambrosia bidentata and 

 psilostachya, Helianthus rigidus and mollis, 

 Coreopsis palmata, Cacalia tuberosa, Hieracium 

 longipilum, Troximon cuspidatum, Castilleia 

 sessiliflora Lithospermum longijlorum, Asclepias 

 Sullivantii, Platanthera lencophea. 



We present these criticisms on the theory we 

 have been discussing, not in a captious spirit, 

 .but under a conviction that the cause of science 

 demands a most i-igorous investigation of all 

 scientific theories. 



Prof.Winchell, in his "Sketches of Creation," 

 manifests a profound knowledge of geological 

 phenomena, and has woven together those 

 phenomena into a world-history, with such skill 

 and with such an agreeable style as to present 

 all the charm of a romance. As a popular resume' 

 of Geology, we believe it will do much good. 



In South America the gigantic Guaduas, an 

 arborepcent grass, attains a height of 60 to 60 

 feet. It blossoms so very seldom, that in the 

 course of four years Humboldt was able only 

 twice to procure the flowers. 



THE OAKS— No. 2. 



(Fig. 172.) 



Swamp White Oal^ {Queycus bicolor) Willd, 



In the June number we gave an account of 

 the White, Bur and Post Oaks. Next in order 

 we may consider the Southern Overcup {Quercus 

 lyrata, Mx.) This is a native of the Southern 

 States, from North Carolina to Florida, and west 

 to Louisiana. It grows in swamps, and attains 

 about the same magnitude and height as the 

 Bur Oak of the Western States. Its leaves are 

 long and smooth, with oblong, nearly acute, 

 lobes, expanded above and contracted below. 

 The acorns are nearly round, and are almost 

 entirely covered by the cup. 



In this section, also, we may briefly notice 

 several species occurring in California, Oregon 

 and the Rocky Mountains. The California 

 White Oak {Quercus Rindsii,^&ni\i.) is a noble 

 tree, having very great resemblance in leaf and 

 general appearance to the White Oak of the 

 Atlantic States, distinguished particularly by 



