710 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



76. HELIANTHUS L. Sunflower. 



Coarse annual or perennial herbs with simple or branched stems, alternate or oppo- 

 site leaves, and often very large headt*; involucre flat to hemispheric, the thick bracts 

 in several series; receptacle flat or convex, chaffy; rays mostly large and showy, 

 yellow, neutral; disk flowers perfect, the corollas brownish, purple, or yellowish; 

 achenes flattened or slightly quadrangular, the pappus of 2 awns or scales, early 

 deciduous. 



KEY TO THE SPECIES. 



Perennials. 



Leaves glaucous and smooth, ciliate, undulate 1. H. ciliaris. 



Leaves not glabrous nor glaucous, not ciliate, flat. 



Leaves soft-villous beneath; stems hispid throughout. 2. H. neomexicanw. 

 Leaves scabrous or at least very rough beneath, not 

 soft-villous; stems glabrous, at least above. 

 Disk flowers dark brown or purple; leaves rhom- 

 bic-ovate; stems pubescent 3. H. subrhomboideus. 



Disk flowers yellow; leaves narrowly lanceolate; 

 stems glabrous or nearly so. 

 Leaves coarsely toothed; bracts hirsute- 



ciliate 4. H. grosseserratus. 



Leaves sparingly denticulate or entire; bracts 



not ciliate or ciliate only at the base. . 5. H.fasrieularis. 

 Annuals. 



Bracts ciliate, hispid, ovate, abruptly acuminate. 



Lower leaves, at least, ovate or cordate, conspicuously 



toothed, dull green 6. H. annuus. 



Leaves lanceolate or narrowly deltoid, obscurely 



toothed or entire, shining • 7. H. aridus. 



Bracts canescent-strigose, not ciliate, lanceolate. 



Leaves green; pubescence of peduncles appressed, 



short 8. H. petiolaris. 



Leaves grayish or whitish; pubescence of peduncles 



long, spreading 9. H. canus. 



1. Helianthus ciliaris DC. Prodr. 5: 587. 1836. Blueweed. Yerba parda. 

 Type locality: "In Mexico prope Reynosa de Tamaulipas." 



Range: Western Texas to southern Arizona and southward. 



New Mexico: Socorro; Tucumcari; Mesilla Valley; Tularosa; Elida; Carlsbad; 

 Artesia; Roswell. River valleys, usually in alkaline soil, in the Lower Sonoran Zone. 



A common and troublesome weed in cultivated fields in the Rio Grande and Pecos 

 valleys. In general appearance this is very unlike our other species. 



2. Helianthus neomexicanus Woot. & Standi. Contr. TJ. S. Nat. Herb. 16: 190. 



1913. 

 Type locality: Mangas Springs, New Mexico. Type collected by Wooton, August 

 19, 1902. 

 Range: Known only from type locality. 



3. Helianthus subrhomboideus Rydb. Mem. N. Y. Bot. Gard. 1: 419. 1900. 

 Type locality: Whitman, Nebraska. 



Range: British America to Nebraska and New Mexico. 



New Mexico: Winsors Ranch; Raton Mountains; Gallinas Planting Station; White 

 Mountains; Baldy; Dulce. Plains and hills, in the Transition Zone. 



