sented by the eastern and western borders of our territory. The traveler going 

 from the summit of the Alleghenies westward to the prairies of Illinois finds the 

 strongly contrasting physical characters of two great areas meeting and blending 

 in Ohio. The western portion of the State, so level and monotonous, has much 

 the aspect of the prairies ; the eastern portion, on the contrary, is occupied by 

 what may be perhaps justly regarded as the foot-hills of the mountains. The 

 Florae of these two regions are as different as their surfaces, and the vegetation of 

 the different portions of Ohio is assimilated to that of the districts to which they 

 are adjacent. 



" differences in geological structure have been principally felt in an east and 

 west direction. The out crops of the various formations occupy belts of surface 

 which have a general north and south bearing ; though near the northern border 

 of the State these bands are strongly curved eastward." 



"It should also be said that over the northern third of the State the soil of 

 most localities is not derived from the rock which immediately underlies them ; 

 but beds of clay, gravel, or sand transported by drift agency conceal the rocky 

 substrata, and by determining the character of the soil have also determined the 

 character of the vegetation, and as a consequence the system of agriculture pur- 

 sued with success. ******* j^ f ew examples will suffice to 

 show the connection which exists between the local character of the vegetation of 

 different districts within the State and the physical influences which have been 

 enumerated above. In the extreme northeastern portion of Ohio, on the highlands 

 back from Lake Erie, the winter temperature is more severe and the fall of snow 

 is much greater than at any point south and west of this. Here are the only ever- 

 green forests in the State, forests of Hemlock — (Abies canadensis) — continuous 

 with those which cover the flanks of the Alleghenies in Northern Pennsylvania. 

 It is especially in this region that the northern plants of our Flora — such as are 

 indicated by Prof. Gray as ranging "from New England to Wisconsin and north- 

 ward " — are found. A number of these, however — especially of the Orchidaceae 

 which grow in cold peat bogs — are also found in the sphagnous swamps which 

 exist in the depressions among the hills of the northern portion of the coal region, 

 and thence stretch around within the basin of Lake Erie to the line of Michigan. 

 These swamps are wholly or entirely covered with a growth of larch or white 

 pine, and are the favorite habitats of the side-saddle flower, two species of Drosera, 

 Cassandra calycidata, several species of Vaccinium, and nearly all the Orchidaceae 

 included in the catalogue. These plants, with some others which grow in the 

 rocky ravines of the streams flowing into Lake Erie — (Aconitum uncinatujji, Cir- 



