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 prcduce 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. Corms.—Another and rarer form of modified 
underground stem is the corm. This is a hard globular 
thickening at the base of the plant. In Panicwm 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 
