232 COMPOSITACEAE (COMPOSITE FAMILY) 



A._ Shrubs. 

 B. Plant spiny; akenes with long cobweb-like hairs. E. 



A. splnescens (bud-brush) 

 BB. Plant not spiny; akenes without cobweb-like hairs. 

 C. Leaves 3-5-cleft or -parted, the lobes linear; 2-6. dm. high. 



D. Heads usually solitary in the axils of ordinary leaves; panicle spikelike. E. 



A. rigida (scab-land sagebrush) 

 DD. Heads clustered; panicle thyrsoid. E. A. trifida 



CC. Leaves entire to 3-toothed or -lobed, but the lobes not linear. 



E. Plant 1-3 dm. high; leaves entire to 3-5-lobed, the lobes cuneate, obovate. E. 



A. arbuscula 

 EE. Plant 5-20 dm. high; leaves entire to 3-toothed, the teeth triangular. E. 



A. trldeiitata (common sagebrush) 

 AA. Herbs or merely shrubby at base. 

 F. Leaves parted or dissected into oblong or linear segments. 

 G. Leaves glabrous or nearly so. 

 H. Leaf lobes filiform, entire. E. A. prescottiana 



HH. Leaf lobes, wider, laciniate or toothed. E. A. biennis 



GG. Leaves pubescent. 

 I. Receptacle woolly. 

 J. Leaves silvery-pubescent, leaf segments short, filiform. E. 



A. frigida (pasture sagebrush) 

 JJ. Leaves not silvery; leaf segments oblong or linear-oblong. E. — Medicinal 

 plant. A. absinthium (wormwood) 



n. Receptacle not woolly. 

 K. Heads 2-3 mm. wide. 

 L. Plants 5-15 cm. high. E. A. petatilida 



LL. Plants 30-70 cm. high. E. A. canadensis 



KK. Heads 4-5 mm. wide. W. C. E. A. borealis 



KKK. Heads 8-10 mm. wide. C. E. A. longipedtmculata 



GGG. Leaves tomentose, at least on the lower surface. 



M. Involucre glabrous or nearly so. C. E. A. discolor 



MM. Involucre densely pubescent or tomentose. 

 N. Leaves with scattered fine white-resinous dots. E. A. atomifera 



NN. Leaves not resinous dotted. E A. ludoviciana 



FF. Leaves entire to cleft or lobed. 

 O. Leaves glabrous or very nearly so on both sides. 

 P. Herbage sweet-aromatic; 4-8 dm. high; branches not drooping; heads 30-60- 

 flowered. E. A. aromatica 



PP. Herbage not sweet-aromatic; 8-16 dm. high; branches drooping; heads 15- 

 2o-fiowered. E. A. dracunculoides 



00. Leaves white-tomentose at least beneath. 

 Q. Involucre persistently white-tomentose. (See MM.) 

 QQ. Involucre glabrous to pubescent but green, not tomentose. 

 R. Involucre cylindric; plant 9-15 dm. high. W. 



A. heterophylla (golden-rod sage) 

 RR. Involucre campanulate. 

 S. Plant about 10 dm. high; involucre green. W. C. E. A. tilesil 



SS. Plant 3-6 dm. high; involucre gray-brown. E. A. lindleyana 



SENECEAE (Arnica Tribe). — Herbs or shrubs. Heads rayless or 

 radiate; receptacle naked (except sometimes hairy in Arnica). Anthers 

 without tails at base though often sagittate. Style branches of perfect 



