236 LEGUMINOSAE (PULSE FAMILY) 
Time of bloom: May to July. 
Seed-time: July to September. : 
Range: Nova Scotia and Ontario to Florida and Texas. Also on 
the Pacific coast and in Arizona. 
Habitat: Cultivated crops, grain fields, meadows, waste lands. 
This plant is often cultivated in the South and West for a cover 
crop and green manure, and also for winter forage. These pur- 
poses it serves very well, particularly if it is used while young, 
before the approach of the fruiting season causes the stems 
to become woody and innutritious; but its hooked burs 
greatly damage the fleeces of sheep, and the 
long vitality of its dormant seeds causes the 
plant to retain possession of the ground 
when it is desired for other crops. (Fig. 
168.) 
Stems six inches to two feet long, branched 
at the base, some prostrate and some 
ascending, spreading in all directions. 
Leaves smooth, with obovate or broadly 
wedge-shaped leaflets, rounded and finely 
toothed at the tips; petioles slender and 
variable in length, with toothed stipules. 
Heads one- to three-fiowered, on peduncles 
shorter than the leaves, the corollas bright 
yellow and about a quarter-inch long. 
Pods _several-seeded, twisted in a_ loose 
spiral of two or three coils, strongly net- 
veined, flattened, with thin keeled edge 
bordered with a double row of hooked 
spines. 
Means of control 
Fic. 168.— Bur Clo- Burn over the ground where plants have 
oa hispida). matured seeds in order to destroy the burs 
on the surface before plowing for other 
crops, which should be such as will require very thorough tillage. 
Seed the ground with other and better clovers that will supersede 
this one. 
