174 OF THE FULCRA, ETC. 



are admirably characterized by the bristles of their 

 leaves, or of j)arts of their leaves, being hooked 

 backward or forward. We therefore accept the 

 272d maxim of Liiina?us's Philosophia Botanica 

 with that limitation which he himself lias allowed in 

 his commentary upon it. " The Pubescence," says 

 he, "" is a ridiculous distinction, being for the most 

 part effaced by culture." After quoting examples, 

 he concludes : '^ We are therefore not to have re- 

 course to the hairiness or spines of plants but in case 

 of absolute necessity." Such necessity every bota- 

 nist will allow to have existed in the Mentha and 

 in Mijosotis scorploides ; and though the degree of 

 pubescence varies from culture, and even its struc- 

 ture be changeable, as in Hedypiiois hispida, E?igi. 

 Bot. t. 554, and hirta, t, 555, its direction is I 

 believe as little liable to exception as any character 

 that vegetables present. 



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