302 Key to the System of 



1367. Finally tall-arborescent. 



A sylvan tree of musky scent ; leaves large, rather firm, 

 mostly ovate-lanceolar, denticulated, underneath beset 

 with silk-like vestiture ; headlets of flowers small, amply 

 paniculated ; flowers comparatively few within each in- 

 volucre ; floral ray white, rather short ; fruits scantily 

 beset with hairlets. "Musk-tree." A. argophyllus. 



Shrubby or rarely somewhat arborescent ... ... 1368 



1368. Quite glabrous 1369 



Variously invested with hairlets ... ... ... 1374 



1369. Leaves decurrent on the branchlets. 



A desert-shrub, hardly tall, always sticky; leaves rather 

 small and distant, mostly from elliptic- to cuneate- linear, 

 entire or oftener imperfectly indented ; headlets of 

 flowers small ; floral ray white ; fruits beset with silk-like 

 vestiture. A. decurrens. 



Leaves simply sessile ... ... 1370 



1370. Leaves linear-cylindrical. 



A swamp-shrub, rather tall and slender, prominently 

 glandular- dotted ; leaves somewhat elongated, acute, 

 closely revolute at the margin ; headlets of flowers very 

 small, corymbously paniculated ; floral ray white ; fruits 

 beset with silk-like hairlets. A. glandulosus. 



Leaves nearly or quite flat ... ... ... ... 1371 



1371. Headlets of flowers corymbously terminal. 



A coast-shrub, finally rather tall, somewhat sticky ; 

 leaves linear, rather long, hardly pointed, almost flat or 

 somewhat revolute at the margin ; headlets of flowers 

 small, corymbously terminal ; floral ray white ; fruits 

 scantily beset with hairlets. A. glutescens. 



Headlets of flowers singly terminal 1372 



1372. Headlets of flowers rather small. 



A desert-shrub, scarcely tall, always sticky ; leaves small, 

 from obovate- to cuneate-spatular, flat, generally some- 

 what denticulated ; headlets of flowers almost sessile, 

 terminating branchlets ; floral ray white or slightly 

 purplish ; fruits beset with silk-like vestiture. 



A. Mueller! . 



