GENUS EUTHAMIA IX MISSOURI t$Q 



For the Missouri species of Euthamia, I offer the following 

 somewhat detailed key: 



i. Stems simple, branched at the top, 9-15 dm. tall, densely short 

 hairy, especially the upper part, the branchlets, pedicels and broad 

 leaves; leaves thinnish, scarcely or obscurely punctate, distinctly 

 3-ribbed, often with a pair of indistinct lateral nerves; heads sessile 

 or very short pedicelled in capitate clusters in a rather open 

 convex corymb, 18-28-flowered; involucre ovoid-companulate to 

 subcylindric, 4-5 mm. high, its yellowish bracts oblong to oblong- 

 lanceolate, slightly viscid; achenes oblong, villous-pubescent. 



1. Euthamia hirtella. 



1. Stems simple, branched at the top, 2.5-5 dm. tall, glabrous, 

 or minutely scabrous, especially the upper part, the branchlets, 

 pedicels and leaves; leaves distinctly 1 -nerved, sometimes with a 

 pair of indistinct lateral nerves, or the larger sometimes 3-nerved; 

 heads sessile or short pedicelled in capitate clusters in a dense flat- 

 topped or loose convex open inflorescence, 10-16 flowered; involucre 

 subcylindric or subturbinate, 3.5-6.5 mm. high, its mostly straw- 

 colored bracts oblong or linear-oblong; achenes top-shaped or 

 .oblong, villous-pubescent. 2. 



2. Leaves linear-lanceolate, spreading, 4-8 mm. wide, yellowish, 

 not strongly punctate, not viscid, distinctly 1 -nerved, or the lower 

 sometimes with a pair of very indistinct lateral nerves; involucre 

 subturbinate, its straw-colored bracts linear-oblong or the lower 

 oblong, scarcely viscid; heads sessile or short pedicelled in a dense 

 flat-topped inflorescence, 10-13 flowered; achenes top-shaped, 

 villous-pubescent. Species of the lower Mississippi Valley. 



2. Euthamia leptocephala. 



2. Leaves narrowly linear, 2-10 mm. wide, light green, punctate, 

 glutinous, distinctly 1 -nerved, or the larger 3-nerved; involucre 

 subcylindric or subturbinate, its straw-colored bracts linear-oblong, 

 or the lower oblong, blunt, viscid; heads sessile or short-pedicelled 

 in capitate cluster in a rather open, scarcely flat-topped inflorescence 

 13-16-flowered; achenes oblong, villous-pubescent. Upper Mississ- 

 ippi basin species of the high prairies. 3. 



3. Leaves lance-linear, taper-pointed, 2-4 mm wide, or oc- 

 casionally wider, obscurely punctate on the upper surface, not viscid 

 or but slightly so; involucre 3-4 mm. high, subcylindric; bracts 

 of the involucre unequal, soft, linear, scarcely glutinous; pedicels 



