WESTERN YARROW 



Achille'a lanulo'sa, syn. A. millefo'lium lanulo'sa 



Wl 



(2 leaves) 



Flower heads small, numerous, 

 stalked, in compact, branched, ter- 

 minal, flattened or round-topped clus- 

 ters (panicles or compound cymes) 2 to 

 4 in. across 



Bracts in a series (involucre) sur- 

 rounding base of flower heads, greenish 

 with pale brown or straw-colored pa- 

 pery margins, overlapping in 3 or 4 

 rows, outer and lower ones much 

 shorter than inner and upper ones 



Outside (ray) flowers of the heads 

 broadly strap-shaped, white, petal- 

 like, few, spreading, seed-producing 



Center (disk) flowers of the heads 

 small, numerous, yellow, tubular, per- 

 fect, seed-producing, inner ones partly 

 enclosed at base by membranous chaffy 

 bracts (paleae) 



Stems densely white-woolly (lanulose), 

 somewhat furrowed, unbranched, erect, 

 up to 3 ft. high 



Leaves tansylike, lanulose, narrowly 

 lance-shaped in outline, much divided 

 and subdivided into very fine, narrow, 

 crowded, ultimate divisions; upper 

 leaves stalkless 



Kootstocks underground, extensive 



Roots numerous, fibrous 



''Seeds" (achenes) hairless, margined, 

 oblong or reversely egg-shaped, without 

 bristles or scales (pappus) at tips 



Western yarrow, also called milfoil, wild-tansy, and woolly yar- 

 row, is a strong-scented, occasionally turf-forming, perennial herb 

 of the mayweed-tansy-sagebrush tribe (Anthemideae) of the huge 

 aster, or composite family (Asteraceae, or Compositae). Its generic 

 name AchiHca is in honor of the legendary Greek hero Achilles, 

 who is credited with first using yarrow to cure wounds ; the specific 

 name Ianiilo8a is a diminutive of the Latin adjective for woolly 

 (from Tana, wool) and refers to the fine, dense, silky-woolly hairs 

 which cover the plant and give it a somewhat grayish appearance. 



Western yarrow is one of the most widely distributed and abun- 

 dant herbaceous species in the 11 far western States. Its range 



