ILLECEBRACEAE (KNOTWORT FAMILY) 133 



and whitened under-surface specked with minute black dots. 

 Flowers very small, scarcely a twelfth of an inch broad, in 

 clusters of two to six on very slender peduncles ; calyx, funnel- 

 shaped, five-ribbed and five-lobed, white or purple ; stamens five or 

 fewer, exserted. The single seed is about an eighth of an inch 

 long, shaped like a reversed pyramid, the sides strongly five- 

 ridged, the top flat. When in the soil the seed retains its vitality 

 for several years. (Fig. 85.) 



Means of control 



In cultivated ground, very thorough and continued tillage in 

 order to prevent the distribution of late-maturing seeds. In 

 meadows the hay should be harvested while the weed is in its first 

 bloom, with repeated cuttings as the plants recover. But rankly 

 infested fields require to be put under cultivation, which should be 

 followed by heavy seeding with clover. 



KNAWEL 

 Sclerdnthus dnnuus, L. 



Other English name: German Knot-grass. 

 Introduced. Annual and winter annual. 



Propagates by seeds. 

 Time of bloom: March to October. 

 Seed-time: May to November. 

 Range : Eastern United States and Canada, 



from Quebec and Ontario to Florida. 



Locally as far inland as Ohio. 

 Habitat: Gardens, lawns, fields, meadows, 



and roadsides. 



An inconspicuous but persistent little weed, 

 as its season of bloom and fruit is both early 

 and late and the seeds when undisturbed in 

 the soil retain their vitality for several years. 



Roots tough and fibrous, sending up a 

 number of slender, light green, fork-branched 

 stems, three to six inches long, usually rough- 

 hairy but sometimes smooth, some erect and 8el*rantk* annuus). 

 some prostrate and spreading on all sides, -x J. 



