102 A TEXT-BOOK OF GRASSES 



The common carpet-grass of our southern states produces 

 strong stolons which, on overhanging banks or in other 

 favorable situations, may reach a length of several feet. 

 Some species produce rhizomes or stolons according to 

 the conditions under which they are growing. Bermuda- 

 grass forms strong rhizomes several inches below the sur- 

 face in cultivated soil but in hard uncultivated soil pro- 

 duces stolons, and not infrequently both may be found 

 in the same mass of sod. 



127. Conns. — Another and rarer form of modified 

 underground stem is the corm. This is a hard globular 

 thickening at the base of the plant. In Panicum bulbosum, 

 a grass found in the mountain valleys of New Mexico 

 and Arizona, these corms are well marked, sometimes as 

 much as an inch in diameter, and may occur in groups of 

 several attached in one mass. Rudimentary corms are 

 found at the base of the stems of timothy, Cinna and 

 many species of Melica. A variety of the tall oat-grass 

 produces corms in moniliform strings. The corms are 

 produced by the thickening of a single internode. If 

 there is more than one corm on the same shoot the con- 

 striction between is the node. In Melica the thickening 

 is greatest at the base of the internode resulting in a flask- 

 shaped corm. Buds arise not on the corms but at the con- 

 strictions, as these are the nodes. The masses of corms 

 mentioned as being found in Panicum bulbosum include 

 together with the living corms persistent old corms at 

 the base of the stems of previous years' growth, these 

 being connected by short rhizomes. 



128. Artificial propagation by means of stems. — Sugar- 

 cane is propagated by planting pieces of the stems or canes, 

 the buds at the nodes developing into shoots. Para-grass 

 and Bermuda-grass are propagated by planting pieces of 



