5 i8 SOILS. 



and doronicoides are perhaps the most generally notable ; while 

 farther west, beginning with Kansas, the " Sunflower State," 

 and its northern neighbor, H. annuus, whether native or intro- 

 duced, becomes conspicuous also. The Silphiums (compass 

 sunflowers) have nearly the same significance, S. laciniatum 

 and perfoliatutn being prominent on the prairies of Illinois and 

 Indiana ; but in land under cultivation they are mostly re- 

 placed by a luxuriant growth of the Ragweed, Ambrosia tri- 

 fida. Various species of Bidens (beggar ticks), notably the 

 B. aristata and cernua, accompany the true sunflowers in the 

 lower grounds of these regions, as do also Heliopsis laevis, 

 Coreopsis triperis and Rudbeckia (Obeliscaria) pinnata. 

 Rudbeckia hirta and purpurea, though also occurring on rich 

 soils, are not characteristic of them. The larger species of 

 golden rods (Solidago), notably ,S\ canadensis, rigida and 

 speciosa (not ordinarily distinguished by farmers) share 

 substantially the distribution of the large sunflowers men- 

 tioned above. Of the Asters, only A. novcc-anglicc serves as 

 a reliable guide to high-class lands in the Middle West, 1 but 

 a very copious growth of asters and solidago of various species 

 is always a welcome indication of land quality, and indicates 

 soils of good lime content, if not absolutely calcareous. 



Leguminous Plants. It is generally understood that most 

 leguminous plants, and among them especially the clovers, in- 

 dicate rich, or rather, calcareous lands. The very large pro- 

 portion of lime contained in the ash of legumes at once creates 

 this presumption, which is fully confirmed by experience so far 

 as our ordinary culture plants of that relationship are con- 

 cerned. The favoring effect of lime on the development of 

 bacteria, so essential to the full development of cultivated 

 legumes, has already been referred to. The favoring effect of 

 gypsum sown even in small amounts with clover and other 

 legumes, may probably be referable to the known action of that 

 salt in promoting nitrification, which in the first stages of 

 leguminous growth is so highly favorable to a vigorous and 

 early start of the crop, and to a more copious production of the 

 nitrogen-assimilating nodules. The quick change noted in 

 meadows and pastures of languishing production so soon as 

 moderately limed, by the appearance of clover among the herb- 



1 In view of its specific designation and the reputed poverty of New England 

 soils, this is rather unexpected. 



