disteibutio:n^ of species 17 



according as these portions were grazed by farm stock or reg- 

 ularly mown for hay. 



Again, Mr. Woodruff e-Peacock states, that the assemblage 

 of plants that form pasture-lands not only varies with every 

 change of soil and climate, but also with any change of the 

 animals that feed upon them ; so that any one experienced 

 and observant can tell, by the presence of certain plants and 

 the absence of others, whether horses, cattle, or sheep have been 

 the exclusive or predominant animals that have grazed upon it. 



Another point of some importance is the greater stability 

 in the flora of meadow as compared with that of pasture land. 

 In the former only one plant was an accidental straggler, while 

 in the latter there were 12, or two-thirds of the peculiar spe- 

 cies. These are mostly rare, and are very often not truly Brit- 

 ish plants, so that they cannot be considered as permanent 

 pasture plants. The more stable meadow flora is no doubt 

 largely due to the fact that few of the late-flowering plants 

 are allowed to produce seed, and though seed may be often 

 introduced by birds or the wind, many of these species soon 

 die out. It thus appears that though pastures are actually 

 richer in species than meadows, yet the latter have a more 

 permanent character, as almost all those peculiar to pastures 

 are comparatively rare and therefore very liable to disappear 

 through very slight changes of conditions. 



These various facts, and many others which cannot be here 

 given, serve to show us how very delicate are the mutual rela- 

 tions and adjustments of plants to their total environment. 

 In proportion as that environment is subject to change of any 

 kind, some rare species die out, while others become diminished 

 in numbers. And what takes place in single fields or other 

 small areas, when closely studied, must certainly occur on a 

 much grander scale over the whole earth, and especially in 

 those countries and periods when great changes of climate or 

 of physical geography are taking place. These detailed studies 

 of " Meadow and Pasture Analysis " — as their author terms 

 them — thus demonstrate on a very small scale that " struggle 



