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 
Diddia 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, weth 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.) 
Fic. 279.— Rough Button- 
weed (Diodia teres). Xi. 
