536 



it. Left unchecked it not only occupies all the space where the grass 

 has become thin, but encroaches aggressively on strong grass sod. 



Wild Carrot. The wild carrot is by no means a new weed, but 

 it is spreading to new localities. It is one of the most aggressive 

 weeds of Canada and the Eastern States, and is rapidly spreading 

 westward, having been found at several points west of the Mississippi 

 River. It seems to thrive well in nearly all kinds of soils, and in 

 all climates from Maine to Georgia. The wild carrot is probably 

 one of the worst weeds in America. The seed fruits are readily at- 

 tached to passing animals and are distributed in that way, or they 

 often remain undisturbed on the plant until winter and are then 

 blown across the snow. Too often they are found in poorly cleaned 

 clover and grass seed. The seeds, inclosed in their hard, spiny coat, 

 retain their vitality for several years, and when once abundant in 

 the soil they are likely to cause trouble during several seasons, even 

 though fresh seeding is prevented. In permanent pasture the 

 persistent mowing of the plants as often as the flower appears will 

 eventually destroy them. They will continue to branch out from 

 the base after each cutting until finally exhausted, so that the first 

 mowing will often appear to increase rather than diminish their 

 numbers. The root may be cut off with a spud some distance below 

 the surface of the ground, a process that usually kills them at once. 

 Pulling the plants by hand when the ground is wet, although some- 

 what laborious, is one the the surest methods of eradication. Sheep 

 eating the young plants will aid considerably in keeping them 

 down. The wild carrot is seldom troublesome in cultivated fields, 

 which indicates that even moderate cultivation will partly subdue 

 it, and that thorough cultivation of the fields, accompanied by the 

 destruction of the weeds in waste places, would reduce it to compara- 

 tive harmlessness. 



Wild Oat. Whether the wild pat and the wild carrot are 

 retrograde developments from the cultivated oat and carrot are ques- 

 tions still unsettled, but doubtless both were introduced into this 

 country as weeds, and they have certainly been propagated here as 

 such. If the wild oat or the wild carrot has appeared in the culti- 

 vated field, it is because the seed of the wild oat or the wild carrot 

 has been sown. The seeds of both are nearly like those of the 

 cultivated plants, and in case of the oat the seed of the wild plant 

 may easily be sown mixed with good oats. Three species of wild 

 oats have been introduced into this country, all quite similar in 

 appearance and all annual weeds. The most common species, A vena 

 fatua, is readily distinguished from the cultivated oat by its usually 

 larger size and earlier and irregular ripening, by the separate florets 

 falling as soon as ripe, and by the long, stout, twisted and 'bent awns 

 borne by the first and second florets. The grain retains its vitality 

 much longer than does the common oat, and may remain buried 

 in the soil several years without germinating. It germinates best 

 when there is an abundance of moisture and the soil is warm. To 

 clear the seed out of the soil, therefore, the land should be stirred 

 when it is warm and as moist as will permit good cultivation. The 



