Xanthium.] COMPOSITE. 153 



19. ACHILL^EA. Linn. Yarrow. 



Involucre ovate, imbricated. Receptacle plane, chaffy. Florets 

 of the ray 5 10, roundish, obcordate. Pappus none. 

 Name ; its healing virtues were said to be first discovered by 

 Achilles. Syngenesia. Superflua. 



1. A. Ptarmica, Linn. Sneeze-wort. Leaves linear-lanceo- 

 late, acuminate, sharply serrated. Br. Fl. 1. p. 367. E. Fl. v. 

 iii. p. 460. E. Bot. t. 757. 



Moist meadows and pastures ; especially in mountainous districts. 

 FL July, Aug. %. Stem 13 feet high, erect, terminating in a rather 

 large corymb, the disk as well as the ray of whose flowers is white. 

 When dried and pulverized, the plant has been employed to excite 

 sneezing. 



2. A. Millefolium, Linn. Common Yarrow or Milfoil. Leaves 

 bipinnate, slightly hairy, their segments linear, toothed, acute ; 

 stems furrowed. Br. Fl. 1. p. 367. E. Fl. v. iii. p. 462. E. 

 Bot. t. 75S. 



Pastures and way sides, common. Fl. all the summer. If. . Flowers 

 small, white, sometimes rose-coloured. 



3. A. tomentosa, Linn. Woolly yellow Milfoil or Yarrow. 

 Leaves bipinnatifid, woolly, the segments crowded, linear, 

 acute ; corymbs repeatedly compound. Br.FL 1. p. 368. E. 

 FL v. iii. p. 462. E. Bot. t. 2532. 



Said to grow in dry hilly pastures in some parts of Scotland. The 

 late Sir James Smith states, that he received it also from Ireland, but 

 does not mention the name of the person who sent it, or where it was 

 found. Fl. Aug. ^. 



20. XANTHIUM. Linn. Bur-weed. 



Barren fl. Involucre, of few scales, with many small, capitate 

 flowers, upon a common receptacle. Calyx none. Corolla 

 obovate, sessile. Anther terminating a tube which is inserted 

 at the base of the corolla. Germen none. The rudiment of 

 a style. Fertile fl. Involucre single, prickly, with two beaks, 

 entirely enclosing two flowers ; the two stigmas only pro- 

 truded from small apertures within the beaks. Calyx none. 

 Corolla none. Fruit 1 -seeded, included in the enlarged and 

 hardened involucre. Name, %avOo<3, yellow* or fair, because 

 an infusion of it was supposed to improve the colour of the 

 hair. Mono2cia. Pentandria. 



1. X. strumarium, Linn. Broad -leaved Bur-weed. Stem 



unarmed ; leaves cordate, three ribbed at the base ; beaks of 



the fruit straight, the prickles hooked. Br. FL 1 . p. 403. E. 



Fl. v. iv. p. 136, E. Bot. t. 2544. 



Said to have been found near Listowel, County of Kerry. Vide, 



T 



