316 Key to the System of 



1426. Marginal flowers about as long as any of the others. 



Annual desert-plant, seldom tall; branches thin ; stem - 

 leaves rather small, from ovate- to elliptic-lanceolar, 

 sessile, clasping, particularly underneath beset with 

 somewhat cottony vestiture ; headlets of flowers solitary, 

 on long thread-like often dark-purplish bractless stalks ; 

 involucral bracts closely oppressed, yellowish, quite 

 smooth, very shining ; pappus of the marginal flowers 

 usually absent, of the others reduced to eight or less 

 bristlets. P. Lessoni. 



Marginal flowers longer than any of the others. 



Annual desert-plant, almost glabrous ; branches very thin, 

 usually numerous ; leaves filiform-linear, quite short ; 

 headlets of flowers on long thread-like bractless stalks ; 

 involucral bracts blunt, pale-yellowish, quite smooth, 

 very shining; marginal flowers with whitish corollar 

 expansion and without any pappus ; fruits glabrous. 



F. Siemssenia. 



CASSZNIA. 



1427. Herbaceous. 



Tall, robust, much beset with interwoven hairlets ; leaves 

 large,, from ovate- to elongate-lanceolar, mostly clasping 

 and somewhat decurrent ; headlets of flowers broadish, 

 in an ample lax panicle ; involucral bracts pale-brownish 

 or pale-yellow, shining, transparent; fruits streaked. 



C. spectabilis. 



Shrubby - 1428 



1428. Involucral bracts pale-yellowish ... ... ... 1429 



Involucral bracts white *... ... ... ... 1430 



1429. Much beset with a close vestiture. 



A desert-shrub ; leaves crowded, cylinclric-linear, quite 

 short, often recurved-pointed ; headlets of flowers in 

 rather elongated somewhat pyramidal panicles ; in : 

 volucral bracts transparent, shining ; flowers four or 

 less within each involucre. Figure 84. C. arcuata. 



Almost glabrous. 



Leaves rather long, cylindric-linear, smooth ; headlets of 

 flowers in somewhat abbreviated panicles ; involucral 

 bracts shining ; flowers few within each involucre. 



C. quiii quef aria. 



