78 STBUCTUIIAL BOTANY. 



CHAPTER XVII. 



FORMS OF SCALE-STEMS. 



230. The Scale-stems are those forms which, with inter- 

 nodes partially or not at all developed, and generally clothed 

 with scales for leaves, scarcely emerge from beneath the soil. 

 They are the creeper and rhizoma (developed), the crown, tuber, 

 corm, and bulb (undeveloped). Their forms are singular, often 

 distorted in consequence of their underground growth and the 

 unequal development of the internodes. They commonly belong 

 to perennial herbs, and the principal forms are described as fol- 

 lows ; but intermediate connecting forms are very numerous, 

 and often perplexing. 



257, Creeper of " Nimble Will," or Witch-grass; a. Bad; M>, bases of culms. 



231. THE CREEPER is either subaerial or subterranean. In the 

 former case it is prostrate, running and rooting at every joint, 

 and hardly distinguishable otherwise from leaf-stems; as the 

 Twin-flower (Linnaea), the Partridge-berry (Mitchella). In the 

 latter case it is more commonly clothed with scales, often branch- 

 ing extensively, rooting at the nodes, exceedingly tenacious of 

 life, extending horizontally in all directions beneath the soil, an- 

 nually sending up from its terminal buds erect stems into the 

 air. The Witch-grass (Triticum rcpens) is an example. Such 

 plants are a sore evil to the garden. They can have no better 

 i-ultivation than to be torn and cut to pieces by the spade of the 

 angry gardener, since they are thus multiplied as many times as 

 there are fragments. 



