284 WEED FLORA OF IOWA 



in the retention of moisture. If the rape is sown in drills about 

 two pounds of seed per acre is sufficient quantity and three pounds 

 if sown broadcast. When the crop has attained a rank growth it 

 may be pastured or removed and fed to stock. Where land is lack- 

 ing in vegetable matter it is good practice to plow the crop under 

 when it is properly manured. The latter is not necessary when the 

 object is to destroy the nettle, as the rank growth of the crop is 

 very effective in completely smothering the weed. 



Hoed crops. Planting of corn or roots is a method much in 

 vogue for the destruction of this vile intruder. As in the previous 

 method the plant should be kept down before seeding time. When 

 the crop appears above the ground the use of horse and hand hoe 

 should not be sparing. When the welfare of the crop prohibits the 

 use of the horse hoe, the hand hoe should be used at intervals until 

 the crop is reinoved; even after this, it is sometimes necessary to 

 give attention to the pest. There is no question about this mode of 

 treatment being effective if properly carried out, but often failure 

 results from negligence during the latter part of the season. 



The Iowa Homestead suggests the following treatment: "Com 

 land that has grown up to horse nettles this year should be burned 

 over, if possible, next spring, as this will destroy many of the 

 seeds. Afterwards the land should be plowed lightly and kept cul- 

 tivated at intervals until somewhat late in the season. A surface 

 cultivator will be all that is necessary, and this need not be run 

 deeper than two or three inches, just enough to effectively, cut the 

 plants off below the surface. By checking the growth several times 

 before planting com the root system becomes much weakened, so 

 that ordinary cultivation the remaining part of the season wiU often 

 keep them completely in check. Where nettles have been going to 

 seed for a number of years it may require considerable tiine to free 

 the land because these will germinate as they are brought near the 

 surface by the various plowings. However, it should be kfept in 

 mind that any perennial root system may be kiUed outright in one 

 season if it is not allowed to develop roots or stems." 



Buffalo Bur {Solarium rostratum Dunal.). 



Description. — Herbaceous; woody when old, somewhat hoary or 

 yellowish, 8 in. -2 ft. high, covered with copious stellate pubescence ; 

 branches and main stems, when it begins to branch, covered with 

 sharp yellow prickles; leaves somewhat melon-like, 1-3 times pin- 



