1. Cauline leaf bases not decurrent along the stem, the stem thus not winged; 

 plants subtomentose when young; leaves thickish 1. H. Hoopesii. 



1. Cauline leaf bases more or less decurrent along the stem to form wings (at 



least for several mm.) on the stem (2) 



2(1). Rays absent (3) 



2. Rays present (5) 



3(2). Plants of southern Arizona and Mexico; annual or biennial; pappus scales 

 broadly ovate to suborbicular, obtuse or rounded, ribless and awn- 

 less 2. H. Thurberi. 



3. Plants of Oklahoma and Texas; perennial or taprooted annuals; pappus scales 



lanceolate or acute (4) 



4(3). Perennial with short fibrous rooted caudex; disk red-brown; pappus scales 

 awned, about 1 mm. long 4. H. flexuosum. 



4. Annual; disk reddish to yellowish; pappus scales acute, less than 0.5 mm. 



long 3. H. microcephalum. 



5(2). Ray flowers neutral, sterile (6) 



5. Ray flowers styliferous, fertile (tardily so in some) (7) 



6(5). Disk yellow; stem nearly simple 5. H. Drummondii. 



6. Disk red-brown; stem branched 4. H. flexuosum. 



7(5). Leaves not uniform; stem not winged throughout; disk more than 15 mm. 



thick, the disk corollas tipped with purple several-celled hairs 



7. H. arizonicum. 



7. Leaves essentially uniform; stem almost entirely winged throughout; disk less 



than 15 mm. thick, the disk corollas yellowish, not tipped with 

 purple several-celled hairs 6. H. autumnale. 



1. Helenium Hoopesii Gray. Orange sneezeweed, owl-claws. 



Perennial with 1 or more leafy stems; stem 3-10 dm. tall, more or less puberu- 

 lent, pubescent or tomentose when young, soon glabrate; basal leaves 1-3 dm. 

 long, oblanceolate to oblong-oblanceolate, entire, wing-petioled; upper leaves 

 lanceolate to lance-ovate, sessile but not decurrent; involucres 7-10 mm. high; rays 

 15-30 mm. long, subentire, golden-yellow to orange; disk flowers about 5 mm. 

 long; pappus about 2-3 mm. long; achenes about 3 mm. long. 



In marshes, wet mt. meadows and in rich soil in conifer forests, in N.M. 

 (widespread) and Ariz. (Apache, Coconino, Greenlee, Graham, Cochise and Pima 

 COS.), June-Sept.; Wyo. to Ore., s. to N.M., Ariz, and Calif. 



This plant is poisonous to sheep causing "spewing sickness." It is poisonous 

 to cattle but not often eaten by them. 



2. Helenium Thurberi Gray. 



Ascending much-branched annual, 4-10 dm. tall, with slender puberulent 

 obviously winged stems and branches; lower leaves oblanceolate, 5-15 cm. long, 

 more or less puberulent and subentire to sharply dentate, narrowing to a slightly 

 winged petiole; upper leaves narrowly lanceolate to linear-spatulate, 2-7 cm. long, 

 entire; peduncles slender, 3-10 cm. long, striate; heads discoid, broadly ovoid to 

 subglobose, more or less corymbose, 5-12 mm. in diameter; involucral bracts 

 linear, 3-7 mm. long, granuliferous and slightly hirsutulous; corollas greenish 

 yellow, faintly tinged with purplish or brownish at tips of lobes, about 1 mm. 

 long, tube virtually lacking, throat campanulate, granuliferous; achenes barely 

 1 mm. long, hirsutulous along low ridges; pappus scales broadly ovate to sub- 

 orbicular, obtuse or rounded, ribless and awnless, about 0.2 mm. long, subhyaline. 



Marshy places along streams, ditches and about ponds, in s. Ariz. (Pinal, Gila, 

 Cochise, Pima and Yuma cos.), Mar.-Aug.; also Mex. 



1678 



