COMPOSITAE. 933 



4. Sideranthus glaberrimus Rydb. NORTHERN SIDERANTHUS. Very similar 

 to the preceding species, but wholly glabrous, or a little puberulent, wholly desti- 

 tute of tomentum. S. Dak. to Wyo., Kans. and Oklahoma. 



20. STENOTUS Nutt. 



Low undershrubs, with coriaceous narrow entire evergreen leaves, scapose or 

 leafy stems, and rather large heads of both radiate and tubular yellow flowers. In- 

 volucre mostly hemispheric, its bracts imbricated in several series, appressed, ovate 

 to lanceolate. Receptacle alveolate. Disk- flowers perfect, their corollas tubular, 

 usually somewhat enlarged upward, deeply 5-toothed. Ray-flowers fertile. An- 

 thers obtuse at the base. Appendages of the style-branches short, lanceolate. 

 Achenes white-villous. Pappus of soft white capillary bristles. [Greek, narrow, 

 referring to the leaves.] About 20 species, natives of western N. Am. 



i. Stenotus armerioides Nutt. NARROW- LEAVED STENOTUS. (I. F. f. 

 3669.) Perennial, tufted from a branched woody caudex, glabrous throughout; 

 flowering stems slender, naked above, or quite leafless, 1-2 dm. high. Basal leaves 

 numerous, narrowly spatulate or linear, acute or acutish, firm, 2-7 cm. long, 2-4 

 mm. wide, entire, narrowed below; stem leaves usually 1-3, sessile, linear, some- 

 times none; head commonly solitary, about 2.5 cm. broad; involucre campanulate, 

 8-12 mm. high, its bracts broadly oval, green, appressed, obtuse or retuse, scari- 

 ous-margined, rays 8-10. In dry, mostly rocky soil, western Neb. to Wyo., Utah 

 and N. Mex. June-July. 



21. ISOPAPPUS T. & G. 



Rough-hairy annual or biennial herbs, loosely paniculately branched, with 

 alternate linear to lanceolate I -nerved entire or somewhat toothed leaves, and small 

 slender- peduncled heads of radiate and tubular yellow flowers. Involucre cam- 

 panulate-cylindric, its appressed lanceolate or subulate bracts in 2 or 3 series. Re- 

 ceptacle alveolate. Ray-flowers 5-12, pistillate. Disk-flowers 10-20, perfect. 

 Anthers not sagittate. Style-appendages narrow, hirsute. Achenes terete, narrowed 

 below, silky-villous. Pappus a single series of rough capillary bristles, nearly 

 equal in length. [Greek, equal pappus.] Two known species, of the southern 



i. Isopappus divaricatus (Nutt.) T. & G. ISOPAPPUS. (I. F. f. 3670.) 

 Annual or biennial, erect, paniculately much branched, slender, rough-pubescent 

 or glandular, 3-9 dm. high. Leaves linear, linear-lanceolate, or the lowest linear- 

 spatulate, acute or cuspidate, dentate with distant teeth, or sometimes entire, 2-7 

 cm. long, 2-6 mm. wide, the uppermost much smaller, subulate or bract- 

 like; heads numerous, 6-10 mm. broad; involucre campanulate. its bracts linear- 

 lanceolate, subulate-tipped, pubescent. In dry soil, Kan. to Tex. east to Ga. and 

 Fla. Aug. -Oct. 



22. SOLIDAGO L. 



Perennial erect herbs, sometimes woody at the base, simple, or little branched, 

 with alternate simple, toothed or entire leaves, and small heads of both tubular and 

 radiate yellow or rarely white flowers, in terminal or axillary panicles, thyrsi, or 

 cymose-corymbose or capitate clusters. Involucre oblong or narrowly campanu- 

 late, its bracts imbricated in several series, the outer successively shorter. Recep- 

 tacle small, flat, or somewhat convex, generally alveolate. Ray-flowers in one 

 series, pistillate. Disk- flowers mostly all perfect, their corollas tubular or narrowly 

 campanulate, 5 -cleft or 5-lobed. Anthers obtuse and entire at the base. Style- 

 branches flattened, their appendages lanceolate. Achenes terete or angled, usually 

 ribbed. Pappus of numerous capillary rough nearly equal bristles in I or 2 series. 

 [Greek, to make whole.] About 100 species, mostly of N. Am., several in Europe, 

 a few in Mex. and S. Am. 



A. Tips of the involucral bracts, or some of them spreading: or recurved. 



Leaves glabrous or glabrate, 1-2.5 dm. long. i. S. squarrosa. 



Leaves rough-ciliate, 2-8 cm. long. 



Leaves green. 2. S. petiolarts. 



Leaves silvery. 3. S. Wardi. _ 



