Part 3, 1916] CARDUACEAE: ANTHEMIDEAE 271 
67. Artemisia silvicola Osterhout, Bull. Torrey Club 28: 645. 
1901. 
Artemisia mexicana silvicola A. Nelson; Coult. & Nels. Man. 569. 1909. 
A perennial herb, with a creeping rootstock; stem 4-6 dm. high, slender, finely white- 
tomentose, striate; leaves many, narrowly linear-lanceolate, 4-6 cm. long, 4-8 mm. wide, all 
entire or the lower with a few short lobes or teeth, acuminate, sessile, loosely floccose but 
soon glabrate and green above, densely white-tomentose beneath; heads numerous in a loose 
leafy panicle, often nodding when young; involucre hemispheric, 4-5 mm. high and about as 
broad; bracts 10-12, in 3 series, grayish, sparingly arachnoid-tomentose, the outer ones ovate, 
half as long as the innermost; inner bracts oval, obtuse, broadly scarious-margined; ray- 
flowers 10-15; corollas cylindric, 1.5 mm. long; disk-flowers 10-20; corollas 2 mm. long; achenes 
1 mm. long. 
TYPE Locality: MacIntyre Creek, a branch of Laramie River, Colorado. 
DISTRIBUTION: Texas, Colorado, and Utah to California and Chihuahua. 
68. Artemisia falcata Rydberg, sp. nov. 
A tall perennial, with a rootstock; stem 6-10 dm. high, loosely floccose; leaves linear or 
narrowly linear-lanceolate, 10-15 cm. long, 2-4 mm. wide, green and glabrate above, white- 
tomentose beneath, the upper simple, falcate, the lower usually with several alternate, spreading 
and strongly faleate, narrow lobes; panicle very large with many ascending, elongate, racemi- 
form branches; involucre broadly campanulate, about 4 mm. high and fully as broad, densely 
floccose; bracts 16-18, in 3 series, the outer ovate, acute, half as long as the inner which are 
oval and obtuse; ray-flowers 5—7; corollas 1 mm. long; disk-flowers 15-18; corollas funnelform, 
glandular-granuliferous, 2 mm. long; achenes 1 mm. long. 
Type collected at Fort Pierre, South Dakota, September 29, 1897, Griffiths 757 (U. S. Nat. 
Herb. no. 592673). 
DistrRrsuTion: South Dakota to Athabasca River, Saskatchewan. 
69. Artemisia Ghiesbreghtii Rydberg, sp. nov. 
A tall perennial, with a rootstock; stem grooved, sparingly tomentose, 5 dm. high or 
more; leaves narrowly lance-linear, 2-8 mm. broad, 5—15 cm. long, green and slightly floccose 
or glabrate above, white-tomentose beneath, the upper entire, the lower often 2- or 3-lobed 
above the middle, if 3-lobed the lateral lobes usually opposite and spreading; inflorescence 
large, open, with elongate racemiform branches and nodding heads; involucre broadly campanu- 
late, 4-5 mm. high and fully as broad, sparingly floccose; bracts 13-15, in 3 series, ovate or 
oval, obtuse, with yellow scarious margins; ray-flowers 5-7; corollas 1 mm. long; disk-flowers 
10; corollas yellow, funnelform, glandular-granuliferous below, 2 mm. long; achenes 1 mm. 
long. 
Type collected in Chiapas, Ghiesbreght 1551 (herb. Columbia Univ.). 
DIstrRIBuTION: Chiapas to State of Mexico. 
70. Artemisia potens A. Nelson, Bot. Gaz. 54: 418. 1912. 
A perennial, with a creeping rootstock; stem simple up to the inflorescence, minutely 
tomentose, pale-green, striate, 4-8 dm. high; leaves alternate, 3-6 cm. long, sessile, pale and 
glabrate above, thinly tomentose beneath, with somewhat revolute margins, linear, simple or 
pinnatifid, with 2-4 divaricate lobes; heads numerous in a dense narrow panicle, crowded; 
involucre 3 mm. high and as broad, hemispheric; bracts 8-10, in 3 series, nearly glabrous, the 
outer ovate, acute, fully half as long as the innermost; inner bracts oval, obtuse; ray-flowers 
10-12; corollas 1.5 mm. long; disk-flowers 10-20; corollas glandular-granuliferous, 2 mm. long; 
achenes 1 mm. long. 
Type LocaLity: Mackay, Idaho. 
DisrrreuTion: Nevada and California to Montana and British Columbia. 
