224 NORTH AMERICAN FLORA [VoLuME 34 
14. Achillea Pecten-Veneris Pollard, Bull. Torrey Club 26: 371. 
1899. 
A perennial, with a creeping rootstock; stem 3-6 dm. high, simple, sulcate, sparingly villous; 
leaves 8-12 cm. long, about 1 cm. wide, the lower oblanceolate and petioled, the upper lance- 
oblong and sessile, bipinnatifid, sparingly pubescent; primary divisions ovate in outline, 
somewhat ascending or spreading; ultimate divisions linear or nearly filiform, spinulose- 
mucronate; heads in branched corymbiform flat-topped panicles; involucre 4~-4.5 mm. 
high, 3-4 mm. broad; bracts 18-20, in 4 series, the outermost ovate, acutish, half as long as the 
elliptic, obtuse innermost; margins narrow, light-brown; ray-flowers about 5; ligules white, 
nearly orbicular, 2-2.5 mm. long, round-lobed; disk-flowers about 20; corollas 2.5 mm. long, 
yellowish-white, glandular-granuliferous; achenes broadly margined. 
TyPE LOCALITY: Guanajuato. r 
DisTRIBuTION: Central and southern Mexico. 
15. Achillea occidentalis Raf.; (DC. Prodr. 6: 24, as synonym. 
1837) Rydb. Bull. Torrey Club 37: 456. 1910. 
Zichelten eaten Schw. in Keating, Narr. Exp. Long 2: 396. 1824. Not A. setacea Waldst. & Kit. 
Ackilice Mitlefolium occidentalis DC. Prodr. 6: 24. 1837. 
A perennial, with a creeping rootstock; stem 3-5 dm. high, striate, silky-villous, mostly 
simple; leaves thrice pinnatifid, sparingly villous, the lower about 1 dm. long, 1—2 cm. wide, 
oblanceolate in outline, petioled, the upper lance-oblong, sessile, about 1 cm. wide; rachis 
merely margined; primary divisions ovate in outline, spreading, the ultimate ones linear and 
spinulose-tipped; heads numerous, in corymbiform panicles; involucre campanulate, 4 mm. 
high, 2.5-3 mm. broad, villous; bracts 18-20, in 4 series, all acutish, the outer lanceolate, half 
as long as the oblong innermost; margins yellowish or straw-colored; ray-flowers 4 or 5; ligules 
white, less than 2 mm. long, nearly orbicular; disk-flowers about 20; corollas yellowish-white, 
2.5 mm. long; achenes 2mm. long, with narrowed margins. (Closely related to the following 
species.) 
TyPE Locatity: Illinois. 
DistRiBuTION: Common from Indiana to Tennessee, Arkansas, Nebraska, and Minnesota, 
but ranging from Massachusetts to Florida and Colorado. 
16. Achillea setacea Waldst. & Kit. Pl. Rar. Hung. 1: 82. 1802. 
A perennial, with a creeping slender rootstock; stem 2—4 dm. high, striate, green, sparingly 
silky-villous, decumbent at the base; leaves twice pinnatifid, green, sparingly pubescent, the 
lower 1—1.5 dm. long, narrowly oblanceolate, petioled, the upper linear, sessile, 5-8 cm. long; 
rachis margined; primary divisions obovate in outline, spreading, the ultimate ones linear, 
spinulose-tipped; heads in open corymbiform panicles; involucre campanulate, 3-4 mm. 
high; bracts 18-20, in 4 series, elliptic, obtuse, the midrib prominent, straw-colored, bordered by 
light-green on both sides; margins straw-colored; ray-flowers 4 or 5; ligules white, less than 2 
mm. long, suborbicular; disk-flowers 10-15; corollas yellowish-white. 
TYPE LocaLity: Near Pest, Hungary. 
x DisTRIBUTION: Edgartown, Massachusetts, and Saguinay County, Quebec; adventive from 
urope. 
I_LustRations: Waldst. & Kit. Pl. Rar. Hung. pl. 80; A. Dietr. Fl. Boruss. pl. 776. 
17. Achillea pannonica Scheele, Linnaea 18: 471. 1844. 
Achillea lanata Spreng.; Willd. Enum. 915. 1809. Not A. lamata Lam. 1778. 
Achillea Millefolium lanata Koch, Syn. Fl. Germ. ed. 2.411. 1844. 
A perennial, with a creeping cylindric rootstock; stem erect, simple, 3-6 dm. high, densely 
silky-villous, grooved; leaves bipinnatifid, densely silky-villous, 4-10 cm.long, the lower petioled, 
linear-oblanceolate in outline, 1-2 cm. wide, the upper linear, sessile, 0.5-1 em. wide; pri- 
mary divisions short, usually close together and ascending; rachis narrowly winged; secondary 
segments densely crowded, usually cleft into a few ovate, callous-mucronate lobes; heads in 
