STEM, LEAF, AND FLOWER 



Roots. — Many grasses spread in all directions by strong run- 

 ners, or rootstocks, as they are called, which are, in reality, 

 underground stems. These runners differ from the true, fibrous 

 roots in consisting of a succession of joints from which upright 

 stems arise, and from which true roots penetrate the soil and 

 anchor the rootstock as it stretches far from the parent plant. 

 Such grasses rapidly take possession of the ground, and as the 

 rootstocks, interlacing in endless network, are thickened with a 

 large amount of nourishing material, these grasses are enabled 

 to endure drouth and unfavourable seasons. Rootstocks of the 

 more vigorous grasses grow many feet in a season, and the thorny, 

 needle-like points of the growing ends often penetrate tubers and 

 roots. 



Grasses that develop only fibrous roots grow more frequently 

 in tufts and bunches. Of these grasses the Bitter Panic-grass and 

 the common Orchard Grass are examples. Perennial grasses are 

 more numerous than annual grasses and may usually be recognized 

 by the presence of sterile shoots growing from the lowest joint of 

 the stem. The greater number of perennial grasses bloom earlier 

 than do the annual grasses, though some perennials are late in 

 flowering, as, for example, the Beard-grasses and the Muhlen- 

 bergias. 



Stems.— Grass stems are divided by joints into internodes (the 

 space between the base of one sheath and that of the next), the 

 point from which each sheath rises being called a node. Although 

 nearly all grasses, with the exception of Indian Corn, Sugar Cane, 

 Gama Grass, and the Beard-grasses, possess hollow stems, which 

 are always closed at the nodes, the rootstocks are usually solid, 

 and the internodes of the young stems are also solid, becoming 

 hollow by the separation of their original pith cells, which cease 

 to grow. The nodes remain solid and, being darker in colour, 

 appear as bands encircling the stems. 



Nodes perform an interesting and important function in rais- 

 ing stems that have been bent down. Internodes play little or 



17 



