Part 1, 1914] 



CARDUACEAE : HELENIEAE 



47 



A slender low annual; stem 1-2 dm. high, branched from near the base, with ascending 

 branches, hirsutulous or glabrate, more or less glandular-hispidulous above; leaves opposite 

 or the upper ones alternate, pinnately 3-7-divided into linear-filiform divisions, sparingly 

 hirsutulous and impressed-punctate; heads numerous; peduncles 1-3 cm. long; involucre 

 obconic or turbinate, about 6 mm. high, 6-7 mm. broad; bracts obovate-spatulate, often tinged 

 with purple, hirsute and glandular; rays none; disk-flowers many; corollas light-yellow, 1.5 

 mm. long; achenes very narrowly obpyramidal, 4-angled, 4 mm. long, hirsutulous on the 

 angles below, otherwise sparingly puberulent; squamellae 8, broadly obovate, almost equaling 

 the corolla, strongly thickened at the base. 



Type locality: Santa Fe, New Mexico. ' 



Distribution : Colorado to Chihuahua. 



36. HYMENOPAPPUS I/Her. Hymenop. 1. 1788. 



Rothia Lam. Jour. Hist. Nat. 1: 16. 1792. 



Annual, biennial, or perennial herbs, often more or less tomentose. Leaves alternate, 

 more or less pinnatifid or the lower rarely entire, in some species crowded at the base. Heads 

 corymbose, discoid or in one species radiate. Involucre hemispheric or campanulate; bracts 

 in 2-3 series, the inner broad, scarious, more or less petaloid, obtuse, yellowish or whitish. 

 Disk-flowers many, hermaphrodite, yellow; tube slender, glandular, puberulent; throat cam- 

 panulate, 5-lobed; lobes mostly ovate. Style-branches with short subulate or conic appen- 

 dages. Achenes obpyramidal, 4-5-angled, striate, hirsute. Pappus of 12-16 membranous 

 squamellae, with or without a distinct midrib, the latter in two species excurrent, or sometimes 

 wanting. 



Type species, Hymenopappus scabiosaeus L'Her. 



Heads discoid. 



Plants more or less glandular at least below. 



Bracts obovate, obtuse; upper part of the plant decidedly 



glandular-hirsute; squamellae usually awn-tipped. 1. H. glandulosus. 



Bracts oblong, acute; upper part of the plant somewhat tomentose, 



not glandular; squamellae usually muticous. 2. H. Nelsoni. 



Plants not at all glandular, usually more or less tomentose, rarely glabrate. 



Squamellae of at least the inner achenes awn -tipped. 3. H. Palmeri. 



Squamellae not awn-tipped, sometimes wanting. 



Corolla-lobes lanceolate, about equaling the short-campanulate 

 throat; biennials. 

 Bracts almost wholly petaloid, white or sulphur-yellow. 



Pappus-squamellae less than a third as long as the corolla- 

 tube; earliest leaves pinnatifid. 

 Bracts of the involucre broadly obovate or ovate; 

 achenes hirsutulous at least on the angles. 

 Bracts with white tips. 

 Bracts with sulphur-yellow tips. 

 Bracts of the involucre oblong, or oblong-obovate 

 with greenish -white tips ; achenes merely puberulent ; 

 leaf -segments very narrow. 

 Pappus-squamellae half as long as the corolla-tube or 

 nearly so; earliest leaves entire. 

 Bracts only with petaloid bright tips. 



Stem-leaves twice pinnate, with linear or linear-filiform 



divisions. 

 Stem -leaves pinnate, with oblong or broadly linear obtuse 

 divisions. 

 Corolla-lobes shorter than the throat; perennials, woody at the 

 base (except H. tenuifolius) . 

 Leaves bi- or tri-pinnatifid with linear or filiform divisions; 

 achenes densely hirsute and strongly striate. 

 Corolla-throat campanulate, not more than twice as long 

 as the lobes. 

 Pappus not hidden by the hairs of the achenes. 



Stem leafy, usually 3 dm. high or more; heads 

 numerous. 

 Plant not densely white-tomentose ; leaves in age 

 glabrate. 

 Biennial; branches and peduncles merely 



ascending. 10. H. tenuifolius. 



Perennial; branches and peduncles erect. 12. H. cinereus. 



4. H. scabiosaeus. 



5. H. sulphur eus. 



6. H. corymbosus. 



7. H. artemisiaefolius. 



8. H. robustus. 



9. H. flavescens. 



