Parr 3, 1916] CARDUACEAE: ANTHEMIDEAE 221 
3. Achillea nigrescens (E. Meyer) Rydberg, sp. nov. 
Achillea Millefolium nigrescens E. Meyer, Pl. Labrad. 65. 1830. 
Achillea borealis Britton, Man. 1013, in part. 1901. 
A perennial, with a creeping rootstock; stem 2—4 dm. high, sulcate, villous, often branched 
above; leaves bi- or tri-pinnatifid, 5-10 cm. long, 1—-1.5 cm. wide, the lower oblanceolate and 
petioled, the upper lanceolate in outline and broadly sessile; primary divisions ovate in out- 
line and spreading, the ultimate ones lanceolate or oblanceolate and with somewhat callous 
mucronate tips; heads in more or less compound corymbiform panicles; involucre campanulate, 
about 5 mm. high, villous; bracts 20—25, in 4 series, the outer lance-ovate and acutish, the inner 
oblong and obtuse; margins dark-brown; ray-flowers about 5; ligules white or pinkish, about 
3 mm. long, suborbicular; disk-flowers about 25; corollas about 3 mm. long, yellowish-white; 
achenes 2.5 mm. Jong, with thick margins. 
TYPE LocaLity: Labrador. 
DistriputTion: Greenland and Newfoundland to Mt. Washington, New Hampshire, Hudson 
Bay, and Mackenzie; Iceland; apparently also on St. Paul’s Island, Alaska. 
ILLUSTRATION: Britt. & Brown, Ill. Fl. ed. 2. f. 4555 (as A. borealis). 
4. Achillea Palmeri Rydberg, sp. nov. 
A stout perennial, with a creeping rootstock; stem 3-6 dm. high, sulcate, sparingly villous, 
branched above; leaves usually less than 1 dm. long, 1-2 cm. wide, bipinnatifid, sparingly 
villous; primary divisions ovate, spreading, the ultimate ones lanceolate, rather conspicuously 
punctate, callous-thickened towards the spinulose-mucronate tips; heads numerous, in broad, 
branched, corymbiform, rather flat-topped panicles; involucre broadly campanulate, fully 5 
mm. high and about as broad, nearly glabrous; bracts about 20, the outer ovate and acutish, 
the inner elliptic and obtuse; margins narrow, dark-brown; ray-flowers usually 5; ligules sub- 
orbicular, about 4 mm. long, white; disk-flowers about 25; corollas fully 3 mm. long, yellowish- 
white; achenes more than 2 mm. long, thick-margined. 
Type collected at Saltillo, Coahuila, or vicinity, November 10-20, 1902, Edward Palmer 326 
(herb. N. Y. Bot. Gard.). 
DistrisuTIon: Coahuila to Vera Cruz and Hidalgo; apparently also southwestern Colorado, 
southeastern Utah, and central California. 
5. Achillea fusca Rydberg, sp. nov. 
A stout perennial, with a creeping rootstock; stem 3-6 dm. high, sulcate, simple, long- 
villous; leaves 1—2 dm. long, 5-10 mm. wide, or the basal ones 2-3 cm. wide, bipinnatifid, 
linear or the lower linear-oblanceolate in outline, long-villous; primary divisions short, ascend- 
ing, ovate in outline, the ultimate ones lanceolate or ovate, callous-thickened towards the spinu- 
lose-mucronate tip; heads in a rather dense rounded corymbiform panicle; involucre about 
5 mm. high and 4 mm. broad, villous; bracts about 20, in 4 series, the outer oval, the inner 
elliptic, all rounded or obtuse at the apex; margins dark-brown, almost black; ray-flowers 
about 5; ligules white or pinkish, suborbicular, round-lobed, 3-4 mm. long; disk-flowers 
20-25; corollas yellowish-white or pinkish, 3 mm. long; achenes nearly 3 mm. long, strongly 
margined. 
Type collected on hillsides, Mt. Paddo, [Washington,] September 28, 1893, Suksdorf 1606 (herb. 
Columbia Univ.). 
DistrersutTion: Washington to Alberta, Vancouver Island, and Yukon. 
6. Achillea arenicola A. Heller, Muhlenbergia 1: 61. 1904. 
A stout perennial, with a long creeping rootstock; stem 3-5 dm. high, densely covered by 
silky-villous white pubescence; leaves bipinnatifid, densely white-villous, 5-10 cm. long, 
usually less than 1 cm. wide, the lower linear-oblanceolate in outline; divisions densely crowded 
and ascending, the ultimate ones ovate or lanceolate, with callous mucronate tips; heads in 
dense round-topped corymbiform panicles; involucre campanulate, 5-6 mm. high, 4-5 mm. 
broad; bracts densely villous, 20 or more in 4 series, the outer ovate, acute, the inner elliptic 
or oblong, obtuse; margins dark-brown; ray-flowers about 5; ligules white, nearly orbicular, 
