335 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Fruit not glabrous, 
Involucral bracts large, usually 15 
mm, or more in diameter when 
mature, sparingly puberulent or 
almost glabrous at maturity: up- 
per leaves with evident petioles ; 
stems itlmost glabrous above. 
Leaves ovate, cordate at the 
base oe 25. A. nyctagined, 
Leaves narrowly ovate to oblong, 
rounted or cuneate at the base, 
hot cordate____. oe 26. A. floribunda, 
ture less than 15 mim. broad, usu- 
ally not more than 10 0 nin, 
densely pubescent; upper leaves 
mostly sessile; stems densely pu- 
bescent above. 
Inflorescence conspicuously bracteate 27. A. latifolia, 
Inflorescence hot couspicuously 
bracteate. 
Bracts broadly ovate, obtuse, 
puberulent; inflorescence — not 
forming a broad cyme; leaves 
oblong-lanceolate, rounded at 
the base, blunt-pointed____- 28, A. oblongifolia. 
Bracts elliptical or narrowly 
ovate, densely hairy ; inflores- 
cence mostly broadly cymose. 
Stamens 5; stem subhirsute 
nimost throughout: leaves 
deltoid-ovate to broadly lan- 
coolate. 29, A, pratensis, 
Stamens 5; stem subhirsute 
below: leaves lanceolate, 
acute, rounded, or tapering 
at the base; bracts usually 
with abundant black hairs _. 380, A. melanotricha, 
Leaves sessile or with very short and inconspicu- 
ous petioles, 
Inflorescence with numerous reduced, bract- 
like lenves oo ~~~ ee B82. 4. bracteata, 
Inflorescence usually not bracteate. 
Stems more or less pubescent below. 
I'ruit) ghibrous 22 22 eee 37. A. carlefoni. 
Fruit not glabrous. 
Stems more or less hirsute. 
Stems hirsute throughout; leaves also 
hirsute, especially on the lower sur- 
face, lanceolate: plant very stout _— 383. A. hirsuta, 
Stems hirsute only about the nodes; 
leaves glabrous and narrower: plant 
more slender —_____- 34. A. pilosa, 
