GENUS 89. 



THISTLE FAMILY. 



i. Achillea Ptarmica L. Sneezewort. White 

 Tansy. Sneezewort- Yarrow. Fig. 4552. 



Achillea Ptarmica L. Sp. PI. 



1/53. 



Perennial from horizontal or creeping rootstocks ; 

 stem glabrous, or slightly pubescent, nearly or quite 

 simple, i-2 high. Leaves linear or linear-lanceolate, 

 sessile and slightly clasping at the base, acute at the 

 apex, regularly and closely serrate, sometimes pubes- 

 cent on the veins beneath, i'-2*' long, ii"-3" wide; 

 heads not very numerous, s"-9" broad ; peduncles pu- 

 berulent ; involucre broadly campanulate, its bracts 

 ovate-oblong, obtuse or obtusish, slightly tomentose ; 

 rays 5-15, white, rather large. 



In moist soil, Newfoundland, New Brunswick and Quebec 

 to Massachusetts and Michigan. Naturalized from Europe. 

 Native also of northern Asia. Goose-tongue. Wild, bastard- 

 or european pellitory. Fair-maid-of-France. Sneezewort- 

 tansy. July-Sept. 



2. Achillea Millefolium L. Yarrow. 

 Milfoil. Fig. 4553. 



Achillea Millefolium L. Sp. PI. 899. 1753. 



Perennial from horizontal rootstocks ; flow- 

 ering stems pubescent, or nearly glabrous, sim- 

 ple, or corymbosely branched above, i-2 

 high. Basal leaves, and those of the numerous 

 short sterile shoots, mostly petioled, sometimes 

 10' long and i' wide, those of the stem sessile, 

 all narrowly oblong or lanceolate in outline 

 and finely dissected into narrow pinnatifid seg- 

 ments, tomentose, pubescent or nearly glabrous ; 

 heads numerous, 2"-3" broad, in terminal com- 

 pound dense, somewhat convex or nearly flat- 

 topped corymbs ; involucre ovoid-cylindric, its 

 bracts oblong, obtusish, pubescent; rays 4-6, 

 white, or often pink or- purple, less than 2" 

 broad. 



In various situations throughout eastern North 

 America, often occurring as a naturalized weed. 

 Native also of Europe and Asia. Old names, san- 

 guinary, thousand-leaf, nosebleed, old-man's-pep- 

 per, soldier's-woundwort, gordaldo. June-Nov. 



3. Achillea lanulosa Nutt. Woolly Yar- 

 row. Fig. 4554. 



Achillea lanulosa Nutt. Journ. Acad. Phila. 7 : 36. 

 1834- 



Similar to the preceding species, perennial by 

 rootstocks, i-2j high, densely silky-woolly 

 nearly all over. Leaves deeply bipinnatifid into 

 narrow lobes and segments, those of the stem 

 mostly sessile ; inflorescence convex, 2'-^' broad ; 

 involucre oblong-cylindric, its bracts greenish- 

 yellow, with brownish margins ; rays \"-2\" broad, 

 white. 



In dry soil, Quebec and Ontario to Michigan, 

 Yukon, south to Oklahoma, Mexico and California. 

 June-Sept. Locally naturalized eastward. 



Achillea ligustica All., differing from A. Millefo- 

 lium by being stouter with loosely corymbose heads, 

 native of Europe, has been found in cultivated ground 

 near Tannersville, New York. 



