quefoil {Potentilla recta) was preserved for six years and showed 

 no tendency to spread. A huge Mexican tea (Chenopodium 

 amhrosioides) was in full bloom on my return to the place in the 

 late summer of 1925; it has not reappeared. During the first 

 year of my occupation lamb's quarter was so abundant that it 

 gave us a fine dish of greens, but it has scarcely been seen since 

 then. Single plants of Deptford pink and winter cress appeared 

 in 1929, a night-flowering catchfly in 1926, an unnamed Cyperus 

 in 1927. 



While weeds are a nuisance in cultivated grounds, they can 

 at least be reduced by the hoe, but in a lawn they are a pest. 

 Excluding white clover, the presence of which is often desired, 

 I have noted nearly thirty kinds of weeds in my limited expanse 

 of lawn. A few of these are dangerous and ruin the lawn if 

 strenuous measures are not used against them. These are the 

 two species of plantain, Plantago Rugelii and P. major, the dan- 

 delion, the mouse-ear chickweed, the crab-grass, and the self- 

 heal. Of these only the last two need any comment. 



Our native self-heal is usually an erect plant, sometimes three 

 feet high, with flower-heads an inch long. The form which grows 

 in lawns is a prostrate creeper with flower-heads seldom more 

 than half an inch long. It has often been said that its prostrate 

 habit is due to the lawn mower which keeps the leaders clipped 

 off; this is not the case. Young prostrate plants from seed have 

 been carefully watched and allowed to grow unchecked, but 

 still retained the creeping form and small heads. In the lawn it 

 forms small but always increasing patches which kill the grass 

 completely. The stems are fragile so that the plants have to 

 be pulled up piecemeal. Fragments of it are scattered by the 

 mower or rake and take root, and seed reproduction is effective 

 also. In 1922 my lawn contained one fair-sized patch; now it 

 has a dozen small ones scattered widely across it. 



Crab-grass does not germinate until late summer. Under 

 ordinary conditions it makes fair-sized plants before blooming, 

 which can be pulled up easily, although care must be used to take 

 every bit of them out. A single fragment left in the soil will 

 bloom as a dwarf and furnish seeds for next year. Last summer 

 was so dry that crab-grass did not germinate at its usual time, 

 and when rains finally came the season was so late that it had 

 to hurry its bloom. As a result it never was a serious weed, but 



