276 ASTER FAMILY 



overlapping the inner ; heads in loose cymes ; leaves opposite, entire ; peren- 

 nial. 



Stems 1-2 ft. high; leaves linear or filiform; rays oval, 

 2-4 mm. long H. Greggii 



HAPLOPAPPUS Cassini 1828 HAPLO PAPPUS 

 (Gr. haploos, simple, pappos, pappus) 



Heads with yellow, pistillate rays or none, disk-flowers yellow, perfect, 

 achenes linear to top-shaped, pappus of hair-like bristles ; receptacle flat to 

 convex, without chaff, involucre usually broad, the bracts more or less im- 

 bricated, often with leaf-like tips ; heads solitary or in corymbs ; leaves 

 alternate, entire to pinnatifid, sometimes spiny-toothed ; annual or perennial. 

 1. Involucre of firm or rigid well-imbricated bracts; 

 pappus dark or reddish 



a. Heads rayless ; achenes silky ; leaves lanceolate 



to spatulate-oblong, toothed H. Nuttdllii 



b. Heads with rays .5-1 in. long; achenes smooth; 



leaves entire 



(1) Stems equally very leafy up to the sessile 



or sub-sessile head ; leaves lanceolate ; 



rays .5 in. long H. Fremontii 



(2) Stems with few sparse leaves above, the 



heads stalked 



(a) Bracts of the involucre ovate to oblong; 



rays nearly or quite an inch long H. croceus 



(b) Bracts oblong to lance-linear; rays .5 in. 



long H. integrifolius 



c. Heads with rays 6-12 mm. long; achenes hairy 



(1) Rays 7-10; leaves narrowly linear, entire; 



stems 1-3 in. high H. multicaulis 



(2) Rays 15-50; leaves mostly toothed to pin- 



natifid 



(a) Stems usually simple with a tuft of basal 



leaves ; leaves entire or spiny-toothed ; 



rays 20-50 



x. Heads usually solitary H. uniflorus 



y. Heads 3-15 H.lanceoldtus 



(b) Stems branching and leafy; leaves 



toothed to pinnatifid, teeth spiny-tipped ; 

 rays 15-30 



