ADAPTATION OF THE TYPES 311 



ence between these two classes lies in the way the new branches or 

 stems develop. 



In bunch grasses the new tillers, which usually arise at a node at 

 or below the surface of the soil, grow up inside the leaf sheath, as in 

 orchard-grass or tall oat-grass. 



In sod grasses the tip of the new branch pushes directly through 

 the base of the leaf sheath and spreads a greater or less distance 

 before ascending. There are several forms of this spreading. 



1. Base of stems prostrate, when the new branch extends hori- 

 zontally for an inch or two and then bends upward, as in timothy. 

 In some cases new roots may develop at the joints from the prostrate 

 portion of the stem. 



2. Stolons are branches much further modified, which extend 

 wholly along the surface of the ground. These may produce new 

 roots at any of the nodes, and also erect ascending stems. Buffalo 

 grass is an excellent example. Bermuda grass sometimes produces 

 stolons when the ground is hard, or rhizomes when the ground is soft. 



3. Rhizomes or root stocks are stems produced underground. 

 They differ from the stolons above ground in the absence of leaves, 

 but are similar in producing roots and ascending stems at the nodes. 

 Blue-grass and brome-grass are good examples. 



Adaptation of the Types. While bunch grasses may make 

 good hay grasses, they are not well adapted to pasture or lawn pur- 

 poses. The land is badly tramped in wet weather. As plants die 

 from various causes or are tramped out the land is not quickly oc- 

 cupied by the spreading of adjacent plants, but weeds are permitted 

 to come in. 



When bunch grasses are sown in pasture, they should be mixed 

 with sod grasses to occupy the vacant spaces. 



While some sod grasses grow tall enough for hay, as brome-grass, 

 not all do, but usually make good pasture or lawn grasses. 



Certain grasses, however, which normally form bunches when 

 permitted to grow tall, form very compact, close turf when kept 

 close cut, as in a lawn or pasture. Sheep fescue and red fescue are 

 good examples. 



Timothy can not be strictly classed with either type. The stems 

 are prostrate for a short distance at the base, forming a slow spread- 



