1913.1 



PUBLIC DOCUMExXT — No. 31. 



37 



with weeds on this account. One of the worst weeds affecting 

 new lawns is crab grass {Digilaria humifusa), but it lasts only 

 a year or two, as a lule. It is mneh more troublesome on dry 

 lawns, wlicre the catch of grass is poor. Frccjucnt close cutting 

 of the grass in the fall is a good preventive, since the seed is 

 not allowed to mature. Two of the plantains, P. lanceolata and 

 P. major, arc troublesome in lawns, more especially where the 

 grass is thin. Cutting plantain a.t different distances from the 

 roots with a special device has not always proved satisfactory, 

 and our observations have shown that when cut in this way a 

 large percentage of the plants renew their growth (Fig. 2). 

 This appears to be true, also, of the dandelion. 



The following table shows the results of cutting plantain 

 stems. Tlie experiments were made by Mr. A. J. Sullivan, a 

 student assistant. 



After being cut the plants were set out in boxes in good soil 

 and under favorable conditions for growth. . They were planted 

 slightly below the surface of the soil to prevent the death of the 

 cut surface. The results do not show much difference as re- 

 gards distance of cutting from the roots, although those plants 

 cut near the roots show a weak and more tardy response. Of 

 the total number of plants cut, 88 started to produce new foliage 

 and 37 failed to respond. 



The stems of plantain are, as a rule, only about % oi" 1 i^^^^^ 

 in length, and if cut quite deep below the surface of the ground 

 a considerable percentage could possibly be destroyed. 



The effects of the prevailing winds on plantain seed are 



