GRASSES — HITCHCOCK 303 



A notable example of the conversion of shallow water of salt 

 marshes ultimately into dry land is seen on the southern and eastern 

 coast of England, and the continental coast opposite, where Spar- 

 tiria townsendii (called " rice grass " in England) has been planted. 

 Great areas are thus being reclaimed from the waters of bays and 

 estuaries. At first there was a fear that the grass Avould stop up the 

 channels in the harbors and interfere with navigation, but it was soon 

 found that the grass could not grow in deep water; it was therefore 

 an aid to navigation rather than a hindrance. 



Throughout our inland regions shallow lakes are being converted 

 into marshes, and these into dry land, by various water plants, 

 jH'ominent among which are grasses (species of CalaTiiagrostis,^ Leer- 

 sia, and Glycerla are especially effective). 



WEEDS WITH RHIZOMES 



Several species of rhizomatous grasses become troublesome weeds. 

 Not only do the plants spread rapidly by the rhizomes, but cultiva- 

 tion serves to propagate the invader, since every joint left in the 

 soil starts a new plant. 



Quackgrass {Agropyron repens), introduced from Europe, is an 

 example of this group. Johnson grass {/Sorghum halepense) , intro- 

 duced from the Mediterranean region, is a great pest in our Southern 

 States because of its strong rhizomes. It has one mitigating char- 

 acter, it is good for forage. Johnson grass was originally intro- 

 duced for forage, but because of its aggressiveness in invading culti- 

 vated fields it lost favor with planters in the South. It is now 

 used for forage chiefly in fields that have become so badly infested 

 that they cannot be profitably put to cotton or other cultivated 

 crops. Bermuda grass {Cynodon dactylorh)^ also from the Medi- 

 terranean region, is a good pasture grass but a bad weed in cotton 

 fields. 



STOLONIFEROUS GRASSES 



Several grasses propagate by creeping stems above ground, called 

 stolons. Buffalo grass {Buchloe dacfyloides), dominant over much 

 of the northern and central part of the Great Plains, once formed 

 lumdreds of miles of turf, supporting countless herds of bison. Its 

 tough sod, held together by interlacing stolons, was used by the 

 early settlers for making sod houses. In Texas another stoloniferous 

 grass {Hilaria helangeri) is dominant on the plains. Rhodes grass 

 {Chloris gayana), a forage grass of Arizona, introduced from Af- 

 rica, produces hard stolons several feet long with internodes as thick 

 as a pipestem. 



