COMPOSITAE. 273 



entire, or merely toothed; heads rather large, solitary or few, 

 usually long-peduncled, many-flowered ; flowers yellow, all fertile; 

 ray-flowers elongated, pistillate, or sometimes none; involucre 

 broadly campanulate, the bracts in 1-2 rows; receptacle naked, 

 fiat; pappus a single series of rather rigid strongly scabrous or 

 barbellate capillary bristles; akenes linear, 5-angled or 5-10- 

 ribbed, somewhat hirsute or nearly glabrous. 



Basal leaves cordate. A. cordifolia. 



Basal leaves lanceolate. A . fulgens. 



Arnica cordifolia Hook. Erect from horizontal rootstocks, 20-40 cm. high, 

 sparsely pubescent; basal leaves ovate or orbicular, deeply cordate, dentate, 

 acute or obtuse, 5-10 cm. long, on petioles about as long; cauline usually 2 

 pairs, less broad, the short petioles margined; heads long-peduncled; involucres 

 turbinate-campanulate, 15-20 mm. high, viscid-pubescent, the linear-lanceolate 

 bracts acute; rays 8-12, yellow, 2-3 cm. long; akenes pubescent. Open woods, 

 Thatuna Hills. 



Arnica fulgens Pursh. Erect, 30-60 cm. high, the crown thickened and 

 rusty-woolly sometimes with creeping rootstocks; whole plant viscid-pu- 

 bescent; basal leaves spatulate-lanceolate, 3-nerved, entire or nearly so, 

 obtuse, 5-12 cm. long; cauline 2 or 3 pairs, sessile, the upper sometimes very 

 small; heads 1-3, long-peduncled; involucres 10-12 mm. high, densely glan- 

 dular-pubescent; rays yellow, 12-16 mm. long; tubes of disk-corollas hairy; 

 akenes pubescent. Moist hillsides, common. The subterranean characters 

 may vary according to soil ; the form without rootstocks has been named as a 

 species, A. pedunculata Rydb. 



407. HOOREBEKIA. 



Herbs or low undershrubs ; leaves alternate, soft or rigid ; heads 

 solitary, terminal, or clustered, many-flowered ; ray-flowers fertile 

 or rarely none; involucre imbricated; bracts with or without 

 foliaceous tips; receptacle flat or flattish; pappus tawny or 

 reddish, of copious and unequal capillary bristles, somewhat 

 rigid; style-branches with appendages; akenes turbinate and 

 linear, terete, angled or more or less compressed. 



Involucre woolly, its bracts not rigid; leaves soft. H. lanuginosa. 

 Involucre glabrous, its bracts rigid; leaves coriaceous. 



Heads large, solitary or few, rayless. H. carthamoides . 



Heads middle-sized, racemose; rays small. H. racemosa. 



Hoorebekia lanuginosa (Gray) Piper. Whole plant covered with a nearly 

 white tomentose pubescence; leaves not rigid, mostly basal and spatulate, 

 the upper narrowly linear, 2-5 cm. long; stems 15-30 cm. high, terminated 

 by a solitary head; involucre hemispheric, woolly, the bracts lanceolate-acute, 

 thin; rays 15-20; akenes white-silky. On gravelly slopes in the Blue Moun- 

 tains. 



Hoorebekia carthamoides (Hook.) Piper. Erect, stout, 30-40 cm. high, 

 rough-pubescent or scabrous, becoming glabrous; basal leaves spatulate- 

 lanceolate, coriaceous, cuspidate, entire or nearly so, 10-40 cm. long; upper 

 cauline smaller, sessile, by rather broad bases; heads solitary, terminal, or 



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