This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
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 obpyra-midal, 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. Type species: Hymenopappus scabiosaeus L'Her.
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. Achenes densely villous.
2. H. corymbosus.
Plant glabrate, or loosely woolly; corolla dull white.
3. H. tenuifolius.
Plant densely white-woolly; corolla yellow.
4. H. flavescens.
Heads few, 6"- 12" broad; corolla yellow; perennial.
5. H. filifolius.
Rothia carolinensis Lam. Journ. Hist. Nat. 1: 16. pl.
1. 1792. Hymenopappus scabiosaeus L'Her.; Michx. Fl. Bor.
Am. 2: 104. 1803. Hymenopappus carolinensis Porter, Mem. Torr. Club 5: 338. 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 commonly numerous, corymbose, 6"- 10" broad; bracts of involucre oblong, ovate or oval, sometimes slightly obovate, thin, bright white, puberulent or glabrate; corolla-lobes about as long as the throat, white; achenes puberulent or pubescent; 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.
Hymenopappus corymbosus T. & G. Fl. N. A. 2: 372. 1842.
Biennial; stem glabrous, or nearly so, corymbosely branched and nearly naked above, 1°- 2° high. Lower and basal leaves petioled, 1-2-pinnately parted into linear or nearly filiform, acute or acutish, glabrous lobes, or somewhat tomentose beneath; upper leaves few, much smaller and less divided, or the uppermost reduced to linear scales; heads corymbose, numerous, 4"- 6" broad; bracts of the involucre 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.