IOO6 FLORA. 



glandular-bearded. Anthers obtuse and entire at the base. Style -branches of the 

 disk-flowers capitellate. Achenes linear, striate. Pappus of 4-6 nerveless acute 

 scales, glabrous or villous. Four species, natives of the southwestern U. S. and 

 northern Mex. 



i. Psilostrophe villosa Rydb. n. sp. NORTHERN PSILOSTROPHE. (I. F. 

 .3958.) Perennial, branched, 1.5-6 dm. high, loosely white-woolly. Basal and 

 lower leaves oblanceolate, entire, dentate or rarely pinnatifid, mostly obtuse, 5-10 

 cm. long; upper leaves sessile, or nearly so, smaller, oblanceolate or spatulate, 

 entire; heads several together in the clusters, 8-10 mm. broad, short-peduncled, or 

 subsessile; rays few, lemon yellow, 4 mm. long, commonly wider, with 2 or 3 

 broad teeth or lobes at the summit; achenes glabrous, or sparingly pubescent; pap- 

 pus-scales linear- lanceolate, glabrous, shorter than the disk-corollas. In dry sandy 

 soil, Kans. to Tex. and Ariz. June-Sept. It has been confused with P. Tagetinae 

 with orange persistent rays 5-10 mm. long. 



73. FLAVERIA Juss. 



Glabrous or minutely puberulent, light green, mostly annual herbs, with oppo- 

 site sessile leaves, and small, i-several-flowered, usually sessile, oblong and densely 

 cymose-capitate heads of tubular, or both tubular and radiate, yellow or yellowish 

 flowers. Involucre of 2-5 narrow, nearly equal, appressed bracts, sometimes with 

 I or 2 additional small exterior ones. Receptacle small, naked. Ray- flower 

 commonly one, pistillate, fertile, sometimes wanting. Disk-flowers 1-15, perfect, 

 fertile, their corollas 5 -toothed. Anthers entire at the base. Style-branches of the 

 disk-flowers truncate. Achenes oblong or linear-oblong, 8-io-ribbed. Pappus none. 

 [Latin, Jlavus, yellow, from its dyeing properties.] About 7 species, natives of 

 America. In addition to the following, 3 others occur in the southern U. S. 



i. Flaveria angustifolia (Cav.) Pers. NARROW-LEAVED FLAVERIA. (I. F. 

 f.|3959.) Annual, glabrous or very nearly so, erect, 3-6 dm. high, little branched. 

 Leaves linear or lanceolate, serrulate or entire, 3 -nerved, acuminate or acute at 

 the apex, sessile by a broad and somewhat clasping base. 3-6 cm. long, 4-8 mm. 

 wide; heads about 6 mm. high, closely sessile in terminal glomerules or these 

 pedunculate from the upper axils; involucre usually of 3 oblong- lanceolate bracts, 

 2-5-flowered; ray equalling or longer than the breadth of the disk; achenes linear, 

 glabrous, about 3 mm. long. In alkaline soil, Kans. and Colo, to Tex., Mex. and 

 N. Mex. Aug.-Oct. 



74. HYMENOPAPPUS L'Her. 



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

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

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

 in i 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 cam 

 panulate 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 i-3-nerved. Pappus of 10-20 thin obtuse 

 scales, sometimes very short or none. [Greek, membrane-pappus.] About 8 

 species, natives of N. Am. and Mex. 



Bracts of the involucre broadly ovate or oval, bright white. i. H. Caroltnensis. 



Bracts of the involucre obovate or oblong, green with whitish or yellow tips. 

 Achenes puberulent or sparingly pubescent on the angles. 



Colored portion of the bracts broad, whitish to sulphur-yellow; corolla whitish. 

 Segments of the leaves, at least of the lower, oblong or broadly linear. 



2. H. sulphureus. 



Segments of all the leaves narrowly linear. 3. H. corymbosus. 



Colored portion of the bracts narrow, yellow ; corolla yellow. 



4. H. flavescens. 



Achenes densely villous or hirsute. 

 \ Pappus over i mm. long, equalling the corolla-tube or nearly so, not hidden by 



the hairs of the achenes; heads numerous. 5. H. tenuifolius. 



Pappus less then i mm. long, shorter than the corolla-tube and hidden by tho 

 hairs of the achenes ; heads few. 6. H. filifolius. 



