34 



WEEDS. 



of the former : germ small ; style filiform, the length of the 

 stamens ; stigma very obtuse, projecting in a point, in many 

 species bifid ; of the latter, germ very small ; style scarcely 

 any; stigmas none. Seeds of the fertile florets solitary; 

 down in most species feathered or capillary; receptacle 

 bristly. 



Essential character. — Receptacle bristly. Florets of the 

 ray funnel-shaped, longer, abortive. 



The "Corn centaury" has a stem one to two feet high, 

 erect, much branched, somewhat woolly ; calyxes serrate, 

 leaves linear, quite entire, the lowest toothed. Root annual, 

 fibrous, black. Leaves hnear-lanceolate, acuminate, some- 

 what woolly ; root leaves entire ; lower stem leaves often 

 pinnatifid or toothed ; upper ones always entire. Flowers 

 terminal, sohtary, peduncled; florets of the disk purplish, 

 regular ; anthers black ; florets of the ray funnel-shaped — 

 always blue when wild ; calyx egg-shaped ; scales lanceo- 

 late. Seeds even-down, many-leaved, unequal, scabrous 

 reddish. It flowers from June to September, and is easily 

 extirpated by constant hoeing to prevent the perfecting of 

 seeds ; and the root being annual, there is no dread of pro- 

 pagation in that way. The oldest writers notice this plant, 

 and it has been mentioned under various names. 



29. The corn Chamomile, or stinking May weed, is a com- 

 mon plant on corn fields. It is the " Anthemis" of botany, 

 and belongs to the class and order " Syngenesia polygamia 

 Superflua" of Linneus, and the natural order " Corymbiferae " 

 of Jussieu. 



Generic character. — Calyx common, hemispherical; scales 

 linear, subequal. Corolla compound, radiate ; corollules 

 hermaphrodite, tubular, numerous in a convex disk ; females 

 more than five in the ray. Proper of the hermaphrodite fun- 

 nel-shaped, five-toothed, erect; of the female ligulate, lanceo- 

 late, sometimes three-toothed. Stamina in the hermaphro- 

 dite : filaments five, capillary very short ; antherss cylindri- 

 cal, tubular. Pistil in the hermaphrodites : germ oblong ; 

 style filiform, the length of the stamens; stigmas two, reflex; 

 in the females germ oblong : style filiform, the length of the 



