54 



COMPOSITAE. 



VOL. 111. 



77. PSILOSTROPHE DC. Prodr. 7: 261. 1838. 

 [RIDDELLIA Nutt. Trans. Am. Phil. Soc. (II) 7: 271. 1841.] 



Branched annual or perennial woolly herbs, often nearly glabrous when old, with alter- 

 nate leaves, and middle-sized heads of both tubular and radiate yellow or orange flowers, 

 corymbose, or clustered at the ends of the branches. Involucre cylindraceous, its bracts 4-10 

 in i series, narrow, equal, densely white-woolly, separate, but erect and connivent, commonly 

 with 1-4 scarious ones within, and occasionally a narrow outer one. Rays broad, becoming 

 papery and whitish, persistent, 5-7-nerved, 2-3-toothed, pistillate. Receptacle small, naked. 

 Disk-flowers perfect, fertile, their corollas with a short proper tube and elongated cylindra- 

 ceous limb, 5-toothed, the teeth glandular-bearded. Anthers obtuse and entire at the base. 

 Style-branches of the disk-flowers capitellate. Achenes linear, striate. Pappus of 4-6 nerve- 

 less acute scales, glabrous or villous. [Greek, referring to the naked receptacle.] 



About 7 species, natives of the southwestern United States and northern Mexico. Type species : 

 P silos trophe gnaphalodes DC. 



i. Psilostrophe villosa Rydb. Plains Psilo- 

 strophe. Fig. 4527. 



P. villosa Rydb.; Britton, Manual 1006. 1901. 



Perennial, branched, 6'-2 high, loosely white- 

 woolly. Basal and lower leaves spatulate, entire, den- 

 tate or rarely pinnatifid, mostly obtuse, 2'-^' long; 

 upper leaves sessile, or nearly so, smaller, linear to 

 spatulate, usually entire ; heads several together in 

 the clusters, 4"-6" broad, short-peduncled ; rays few, 

 lemon-yellow, commonly as wide as long, with 2 or 

 3 broad teeth or lobes at the summit; achenes gla- 

 brous, or sparingly pubescent ; pappus scales linear- 

 lanceolate to oblong-lanceolate, glabrous, shorter 

 than the disk-corollas. 



In dry sandy soil, Kansas to Texas and Arizona. In- 

 cluded, in our first edition, in P. Tagetinae (Nutt.) 

 Kuntze, which has much larger yellow rays. June-Sept. 



78. FLAVERIA Juss.; Gmelin, Syst. 1269. 1791. 



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

 entire or serrate 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 or setose. Ray-flower commonly only I, pistil- 

 late, 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 the warmer parts of America. In addition to the following, 3 others 

 occur in the southern United States. Type species : 



Flaveria chilensis Gmelin. 



i. Flaveria campestris Johnston, 

 veria. Fig. 4528. 



Plains Fla- 



Flaveria campestris 

 1903. 



Johnston, Proc. Am. Acad. 39 : 287. 



Annual, glabrous, erect, i-2 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, \'-2\' long, 2"-^" wide; heads 

 about 3" high, closely sessile in terminal glomerules or 

 these pedunculate from the upper axils ; involucre of 3 

 oblong-lanceolate bracts, 2-5-flowered ; ray equalling or 

 longer than the breadth of the disk; achenes linear, gla- 

 brous, about li" long. 



In alkaline soil, Missouri to Colorado, Texas and Mexico. 

 Aug.-Oct. In our first edition included in the Mexican F. 

 angustifolia (Cav.) Pers. 



