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 heads; 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 awos or scales, early 

 deciduous. 



KEY TO THE SPECIES. 



Perennials. 



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



Leaves not glabrous nor glaucous, not ciliate, flat. 



Leaves soft- villous beneath; stems hispid tliroughout. 2. H. neomexicamis. 

 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 hii-sute- 



ciliate 4. H. grosseserratus. 



Leaves sparingly denticulate or entire; bracts 



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

 Annuals. 



Bracts ciliate, hispid, ovate, abruptly acuminate. 



Lower leaves, at least, ovate or cordate, conspicuously 



toothed, dull green 6. H. annuiis. 



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. JS. peiiolaris. 



Ijeaves grayish or whitish; pubescence of peduncles 



long, spreading 9. H. canus. 



1. Helianthus ciUaris 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 Pecoa 

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



2. Helianthus neomexicanus Woot. & Standi. Contr. U. 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. 



