10 



HANDBOOK 14 8, U.S. DEPARTMENT OF AGRICULTURE 



1. Twigs not spiny-tipped. 

 6. Plants with spines. [Alternate 6, p. 18.] 



7. Twigs and young spines (the hardened, persistent midribs of 

 the primary leaves) densely white- woolly-hairy; spines becom- 

 ing rigid, spreading or recurved, and with clustered, green, 

 hairless, linear, secondary leaves in their axils by the second 

 season; flowers 5-9, all alike, in flower heads surrounded by 

 4-6 woolly-hairy bracts in a single row; flower-head bracts per- 

 sistent after the hairy -tufted "seeds" (achenes) have fallen; 

 stiff, much-branched shrubs to nearly 5 feet high; probably (if 

 ever browsed) poisonous to livestock; dry, rocky sites, e. Oreg., 



e. Wash cottonthorn horsebrush (fetradymia spinosa). 



7. Twigs and spines not as above; leaves palmately 3- to 7-lobed 

 or cleft, round in outline, square-cut, wedge- or heart-shaped at 

 base, clustered at tips of short, spurlike twigs or solitary at 

 joints (nodes) on young or fast-growing shoots; stems armed 

 with simple or 3-forked (sometimes 7- to 9-parted) spines 

 around leafstalk bases, often also with scattered prickles and/ 

 or bristles; pith spongy; flowers and berries stalked, in stalked 

 and bracted clusters (racemes) ; berries tipped by withering- 

 persistent flowers; erect or spreading shrubs, often with arching 



' Mi 



v. V 



Persistent flower-head 

 bracts 





/ 



/' 





Secondary leaves clustered 

 in spine axils 



F-494017 



Cottonthorn horsebrush 



