554 COMPOSITAE (COMPOSITE FAMILY) 



yellow, conspicuously longer than the glabrous involucre: pappus a crown 

 of hyaline scales which are more or less connate and fimbriate-lacerate at 

 summit, the fringe dissected into bristles or hairs somewhat simulating those 

 of the margin of the achene. Rocky canons, etc.; southern Colorado, New 

 Mexico, and Arizona. 



63. HYMENOPAPPUS L'Her. 



Perennial or biennial herbs with sulcate-angled erect stems, alternate 

 mostly once or twice pinnatifid or parted leaves, and corymbosely cymose 

 or solitary pedunculate heads of yellow or white flowers. Involucre cam- 

 panulate, many-flowered, of 6-12 mostly appressed bracts with scarious- 

 membranaceous usually colored tips. Rays none; disk-corollas numerous, all 

 alike, with narrow tube, abruptly dilated throat, and reflexed or widely spread- 

 ing lobes. Style-branches with short and thick conical appendages. Achenes 

 obpyramidal, 4-5-angled, with attenuate base, the faces 1-3-nerved. Pappus 

 of 10-20 thin-scarious and mostly hyaline obtuse scales; sometimes very short 

 or obsolete. 



Stems leafy throughout, mostly corymbosely branched and with numer- 

 ous heads. 



Pappus evident and nearly as long as the corolla-tube . . . 1. H. tenuifolius. 

 Pappus either wanting or hidden by the hairs of the achenes . . 2. H. luteus. 

 Stems leafy below, upward the leaves reduced, few or wanting; heads 



not numerous. 

 Stems somewhat branched, 2-5 dm. high. 



Pappus hidden by the hairs of the achene . . . . . 3. H. filifolius. 



Pappus evident, nearly as long as the corolla-tube . . . .4. H. arenosus. 



Stems scapose, less than 2 dm. high . . . . . . . 5. H. scaposus. 



1. Hymenopappus tenuifolius Pursh, Fl. 2: 742. 1814. Lightly tomen- 

 tose, or soon glabrate and green, leafy: leaves rather rigid, once or twice 

 pinnately parted into very narrowly linear or filiform divisions, the margins 

 soon revolute: heads only 6-10 mm. high, numerous and cymose; involucre 

 rather erect and close; the bracts oblong-obovate, greenish with whitish apex 

 and margins: corolla dull white: achenes long-villous. Eastern Wyoming 

 and southward through Nebraska and Kansas. 



2. Hymenopappus luteus Nutt. Trans. Am. Phil. Soc. 7: 374. 1841. 

 Stems 1 or more from each crown; crowns densely lanate; stems spreading, 

 1-3 dm. long: leaves white-tomentose; basal leaves numerous, petioled, 

 pinnateiy parted; the pinnae irregularly pinnatifid into 3-9 short-linear di- 

 visions; cauline leaves similar but smaller and narrower: heads loosely 

 corymbose-paniculate, when fully developed, about 1 cm. high; bracts of the 

 involucre oblong, obtuse, truncate or even retuse, greenish and sparsely lanate, 

 margins and tip membranous: flowers numerous (40-60); corolla yellowish- 

 white, tube glandular, about half the length of the campanulate throat; lobes 

 much shorter than the throat: pappus wanting or obscure and short: achene 

 softly pubescent. Desert areas; Wyoming, Colorado, and Utah. 



3. Hymenopappus filifolius Hook. Fl. Bor. Am. 1 : 317. 1833. Tomentose- 

 canescent, or somewhat denudate and glabrate, leafless above; stems 1.5-3 

 dm. high, sometimes scapiform: leaves nearly as in the last, or of more fili- 

 form rigid divisions: heads 8-12 mm. high, few; bracts of the involucre oblong 

 or obovate-oblong, largely green or else white-woolly, the tips whitish or 

 purplish-tinged: corolla yellowish- white or sometimes clea$ yellow: achenes 

 very long-villous. From Nebraska and Montana to New Mexico and southern 

 California. 



4. Hymenopappus arenosus Heller, Bull. Torr. Bot. Club 25: 200. 1898. 

 Stems clustered, leafy below, branching, floccose-tomentose: leaves thrice 

 or the upper ones only twice pinnately divided, the divisions all linear, from 

 0.5-2 cm. long, petioled: heads corymbosely cymose, on stoutish peduncles, 

 1 cm. high; flowers yellow; bracts of the involucre obovate-oblong, the mar- 

 gins thin, whitish, floccose-tomentose at base: corollas 5 mm. long, the tube 

 nearly half the length, the triangular-lanceolate lobes little more than one 



