1006 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. NORTHERN PSILOSTROPHE. (I. F. 



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

 lower leaves oblanceolate, entire, dentate or rarely piimatifid, 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, 01 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, flavus, 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. Flaveiia campestris Johnston. NARROW. LEAVED FLAVERIA. (I. 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, mostl^ 

 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 lobe d 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. Carolinensis. 



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. //. sulphureus. 



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



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



4. //. 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 the 

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



