Genus 74.] 



THISTLE FAMILY. 



445 



74. HYMENOPAPPUS I/Her.; Michx. Fl. Bor. Am. 2: 103. 1803. 



Perennial or biennial, erect herbs, with angled stems, alternate or basal, mostly pinnatifid 

 or dissected leaves, and corymbose or solitary, small or rather large discoid heads, of white 

 or yellow flowers. Involucre hemispheric or broadly campanulate, its bracts 6-12 in 1 or 2 

 series, nearly equal, mostly appressed, colored, petal-like, the margins and apices scarious. 

 Receptacle small, naked. Rays none. Disk-flowers all perfect and fertile, their corollas 

 with slender tubes and reflexed or spreading campanulate 5-lobed limbs, the lobes ovate. 

 Anthers entire at the base. Style-branches with short conic appendages. Achenes obovoid 

 or obpyramidal, 4-5-angled, the faces usually prominently 1-3-nerved. Pappus of 10-20 

 thin obtuse scales, sometimes very short or none. [Greek, membrane-pappus.] 



About 7 species, natives of southern and central North America and Mexico. 



Bracts of the involucre broadly ovate or oval, bright white. 1. H. Carolinensis. 



Bracts obovate to oblong, green or with white tips. 

 Heads numerous, 4" -6" broad; biennials. 



Achenes puberulent; corolla white. 2. H. cotymbosus. 



Achenes densely villous. 



Plant glabrate, or loosely woolly; corolla dull white. 3. H. tenuifolius. 



Plant densely white-woolly; corolla yellow. 4. H. flavescens. 



Heads few, 6"-i2" broad; corolla yellow; perennial. 5. H. filifolius. 



i. Hymenopappus Carolinensis (Lam.) Porter, 

 pappus. (Fig. 3960.) 



Rothia Carolinensis Lam. Journ. Hist. Nat. 1: 16. 



pi. 1. 1792. 

 Hymenopappus scabiosaeus L'Her. ; Michx. Fl. 



Bor. Am. 2: 104. 1803. 

 Hymenopappus Carolinensis Porter, Mem. Torr. 



Club, 5: 33S. 1894. 



Biennial: stem woolly-pubescent or glabrate, 

 leafy below, corymbosely branched and nearly 

 naked above, 2-3 high. Basal and lower leaves 

 petioled, 4 / -6 / long, 1-2-pinnately parted or 

 deeply pinnatifid into linear or oblong, obtuse 

 or obtusish lobes, more or less white-tomentose 

 beneath, green and glabrate above; upper leaves 

 few, smaller, sessile, less divided; heads com- 

 monly numerous, corymbose, 6 // -io // broad; 

 bracts of involucre oblong, ovate or oval, some- 

 times slight^ obovate, thin, bright white, pu- 

 berulent or glabrate; corolla-lobes about as long 

 as the throat, white; achenes puberulent or pu- 

 bescent; pappus of very small nerveless scales, 

 shorter than the width of the top of the achene. 



In dry sandy soil, Illinois to Texas, east to 

 South Carolina and Florida. March-June. 



White-bracted Hymeno- 



2. Hymenopappus corymbdsus T. & G. 



Corymbed, or Smooth White Hymeno- 

 pappus. (Fig. 3961.) 



Hymenopappus corymbosus T. & G. Fl. N. A. 2: 372. 

 1842. 



Biennial; stem~glabrous,or nearly so, corymbosely 

 branched and nearly naked above, i-2 high. 

 Lower and basal leaves petioled, 1-2-pinnately 

 parted into linear or nearly filiform, acute or acut- 

 ish glabrous lobes, or somewhat torn entose beneath; 

 upper leaves few, much smaller and less divided, or 

 the uppermost reduced to linear scales; heads cor- 

 ymbose, numerous, 4 // -6 // broad; bracts of the in- 

 volucre obovate to oblong, puberulent, their tips 

 greenish white; corolla white, its lobes about as long 

 as the throat; achenes puberulent; pappus-scales 

 small, nerveless, shorter than the width of the top 

 of the achene. 



On dry prairies, Nebraska to Texas. Summer. 



