434 CONTRIBUTIOiJ^S FROM THE NATIONAL, HERBARIUM. 



8. Artemisia gnaphaloides Nutt. Frequent at low altitudes, on dry, open or 

 brushy slopes or in low thickets; rarely found on open slopes above timber line. 

 Alta. to Colo., Tex., Mo., and Ont. — -Plants whitish, 30 to 60 cm. high, often forming 

 large patches; leaves lanceolate or oblanceolate, 2 to 10 cm. long, the upper ones 

 entire, the lower mostly toothed, sharp-pointed; heads 4 mm. high, white- woolly, 

 in narrow spikelike panicles. 



9. Artemisia floccosa Rydb. Low thickets below Lake McDermott, and brushy 

 slopes along Appekunny Creek. Oreg. to Mont, and Wyo. — Plants 20 to 40 cm. high, 

 often forming dense clumps, whitish; leaves 3 to 5 cm. long, the upper ones often 

 entire; heads about 4 mm. high, white-woolly. 



10. Artemisia diversifolia Rydb. Frequent at low and middle altitudes, on open, 

 gravelly or grassy slopes or dry prairie. B. C. to Calif., Colo., and Nebr. — Plants 

 whitish, 30 to 80 cm. high, often forming broad dense clumps; lower leaves 5 to 10 

 cm. long, with 3 or 5 lobes pointing forward, the upper leaves mostly entire; heads 

 3 to 4 mm. high, woolly, in narrow panicles; flowers pale yellow. 



It is probable that this and A. floccosa are merely forms of A. gnaphaloides . 



24. PETASITES L. 



1. Petasites sagittata (Pursh) A. Gray. Sweet coltsfoot. Not common, but 

 found in swampy meadows below Lake McDermott and at St. Mary and Grinnell 

 Lake. Alaska to Colo., Minn., and Lab.- — Perennial, with thick rootstocks; flower 

 stalk with bracts but no leaves, 20 to 30 cm. high, bearing a few heads; leaves all 

 rising from the ground, long-stalked, heart-shaped or triangular, 15 to 40 cm. long, 

 shallowly toothed, green on the upper side, white-woolly beneath; heads 7 to 10 mm. 

 long, the flowers purplish or whitish. 



The flowers appear early in the season. The leaves are conspicuous and re- 

 mind one somewhat of those of burdock. 



25. ARNICA L. Aenica. 



Perennials with rootstocks, more or less hairy; stems leafy, the leaves opposite, 

 entire or toothed; heads 1 or few, large, the bracts equal in length; rays yellow, 

 rarely absent; pappus of slender, white or brownish bristles. — The species are difficult 

 to distinguish, and they are imperfectly understood; it is doubtful whether all those 

 listed below are valid. The arnica used as a drug is obtained from a European species 

 of this genus. In our species the rootstocks have the characteristic arnica flavor and 

 odor. The arnicas are among the most abundant and showy flowers of the park. 



Rays none 1. A. parryi. 



Rays present, showy. 

 Pappus brownish or yellowish, finely hairy. 

 Stem leaves narrowly lanceolate, entire or minutely toothed, finely hairy; 



achenes hairy and with fine glands 2. A. longifolia. 



Stem leaves lanceolate or ovate, usually coarsely toothed, coarsely hairy; achenes 

 hairy but without glands. 



Basal leaves not heart-shaped 3. A. mollis. 



Basal leaves heart-shaped 4. A. diversifolia. 



Pappus white, merely roughened, not hairy. 



Basal leaves heart-shaped or broadly ovate, usually long-stalked. 



Achenes densely hairy 5. A. cordifolia. 



Achenes glabrous or glandular or with a few scattered hairs above. 



Heads (from base to end of pappus) 10 to 12 mm. high .... 6. A. gracilis. 

 Heads 15 to 18 mm. high. 



Lower stem leaves stalked; heads turbinate 7. A. latifolia. 



Lower stem leaves sessile; heads campanulate 8. A. granulifera. 



