400 



RUBIACEAE (MADDER FAMILY) 



Means of control 



Sow clean seed. Harvest infested meadows before the flowers 

 mature, particularly if the hay is intended for market. Ground 

 badly fouled with the weed should be put under cultivation for the 

 purpose of destroying its perennial roots. Good drainage is a dis- 

 couragement to the growth of this plant, for it prefers the soil damp. 



ROUGH BUTTONWEED 



Diodia teres, Walt. 



Native. Annual. Propagates by seeds. 



Time of bloom : July to September. 



Seed-time: August to October. 



Range: Connecticut to Missouri, southward to Florida, Texas, 

 and New Mexico. 



Habitat: Dry soil ; cultivated ground, grain and clover fields, road- 

 sides, and waste places. 



This plant is very resistant to drought, having a slender taproot, 

 often nearly a foot long, fringed with fine feeding rootlets. Stems 

 several from the same root, four inches 

 to two feet in length, ascending or some- 

 times prostrate, usually rough-hairy. 

 Leaves opposite, lance-shaped to linear, 

 rough-hairy on both sides, acute, rigid, 

 sessile, the margins revolute in dry 

 weather. Flowers usually solitary in the 

 axils, the corolla funnel-form, five-lobed, 

 about a quarter-inch long, pale purple ; 

 stamens four, with anthers exserted ; 

 style with two-parted stigma. Fruit 

 small, obovoid or top-shaped, about one- 

 sixth of an inch long, hard and rough- 

 hairy, crowned with the four persistent 

 calyx-teeth ; it has two or occasionally 

 three cells, and when ripe usually splits 

 into two closed carpels. These seeds are a frequent impurity of 

 southern grain and clover seed ; and the weed is most undesirable 

 company for those crops, as it absorbs much of the soil fertility. 

 (Fig. 279.) 



FIG. 279. Rough Button 

 weed (Diodia teres). XT- 



