CHAPTER II. 



WEED GRASSES AND NATIVE GRASSES. 



SECTION I. WEEDS. 



It is very difficult to say what grasses are weeds, for 

 what is regarded as a valuable plant under some circum- 

 stances becomes a noxious weed elsewhere. A weed is a 

 plant growing out of place, and any grass, no matter how 

 good it is, is a weed if it is occupying ground that would 

 support some better grass. On the other hand, grasses 

 almost universally regarded as weeds become of great utility 

 under special circumstances, and therefore at once lose their 

 objectionable distinction. Several of the grasses mentioned 

 in the last chapter, e.g., Chewings Fescue, Poa pratensis, 

 Creeping Bent and Danthonia are often regarded as weeds, 

 while some to be mentioned here among the weeds, e.g., 

 Agropyrum repens, have a distinct Sphere of utility. The 

 terms "weed" and "pasture grass" are therefore only 

 relative to the condition under which the grasses are found. 



Occasionally grasses and other plants that are not of 

 sufficient value to sow, come up spontaneously, and occupy- 

 ing spaces that would otherwise be vacant, provide valuable 

 fodder. Such plants are then hardly weeds, but are known 

 as volunteers. Examples are Poa annua and Trifolium minus. 



Twitch or Couch is a name that is given to any grass 

 with a rhizome or creeping underground stem. Such a grass, 

 once it is in the ground, is very hard to get out, for the 

 instruments of cultivation break and scatter the rhizomes, 

 and each piece becomes a new plant. There are some six 

 or seven twitches common in New Zealand, and frequently 



