DESCRIPTIVE MANUAL 241 



Wallace's Farmer says concerning this weed: "We would ad- 

 vise our correspondent to plow this field as soon as possible 

 and prepare his seed bed for winter wheat. By plowing it again 

 next August he will undoubtedly weaken the stand. He will 

 fail, however, unless in working his corn he uses surface cultiva- 

 tion. These weeds have no doubt been distributed through the 

 field during the three years it was in corn by using a shovel cul- 

 tivator, which takes up the roots and carries them over the field 

 in the same way that many northern farmers are now seeding their 

 fields with quack grass and damaging them to the extent of from 

 five to twenty dollars per acre. By giving these two thorough 

 August plowings and taking care of the roots that may be thrown 

 up, then preparing the seed bed very thoroughly for corn and 

 giving it as far as practical surface cultivation, he will probably 

 get rid of these noxious weeds." 



Climbing Milkweed (Gonolobus laevis Michx.). 



Description. — A climbing perennial; leaves oblong, cordate with 

 a deep, narrow sinus; flowers borne in axillary umbel-like cymes, 

 5-10 flowered, large greenish flowers; calyx 5-parted; corolla 5- 

 parted, wheel-shaped, the lobes narrowly linear-lanceolate, obtuse, 

 larger than the calyx; anthers horizontal under the flattened 

 stigmas ; pollen masses 5 pairs, follicles with soft warty projections. 



Distribution. — Troublesome in woods and fields in the southern 

 states. It is reported as troublesome from a few counties in south- 

 ern Iowa. 



Extermination. — This perennial weed is as difficult to destroy as 

 common milkweed. Give thorough cultivation. If this will not suf- 

 fice get the field into a meadow. 



CONVOLVULACEAE, MORNING-GLORY FAMILY. 



Few economic plants. Sweet potato and cultivated morning glory 

 are representatives. 



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