330 



COMPOSITAE. 



[Vol. III. 



I. Isopappus divaricatus (Nutt.) 

 T. & G. Isopappus. (Fig. 3670.) 



Inula divaricata Nutt. Gen. 2: 152. 1818. 

 Aplopappiis divaricalus A.. Gray, Syn. KI. i: Parts, 130. 



1884. 

 Isopappus divaricatus T. & G. Fl. X. .\. 2: 2Tf). 1S41. 



Annual or biennial, erect, paniculately much 

 branched, slender, rough-pubescent or glandular, 

 i°-3° high. Leaves linear, linear-lanceolate, or the 

 lowest linear-spatulate, acute or cuspidate, dentate 

 with distant teeth, or sometimes entire, \'-}/ long, 

 1"-}," wide, the uppermost much smaller, subu- 

 late or bract-like; heads numerous, 3"-5" broad; 

 involucre campanulate, its bracts linear-lanceolate, 

 subulate-tipped, pubescent, peduncles very slender 

 or filiform. 



In dry soil, Kansas to Texas, east to Georgia and 

 Florida. Aug. -Oct. 



22. SOLIDAGO L. Sp. PI. 878. 1753. 

 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 campanulate, its bracts imbricated in 

 several series, the outer successively shorter. Receptacle 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 85 species, mostly of North America, 2 or 3 in Europe, a few in Mexico and South 

 .America. 



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

 Leaves glabrous or glabrate, 4'-io' long. i. S. squairosa. 



Leaves rougheiliate, r-2' long. 2. 6". petiolaris. 



B. Tips of the involucral bracts all erect and appressed. 

 ^ Heads in axillary clusters, or also in a terminal spike-like, sometimes branched thyrsus. 

 !. Heads 2"-3" high, chiefly in axillary clusters; achenes pubescent. 

 Stem and branches terete; leaves lanceolate to oblong. 3. .S. caesia. 



Stem and branches grooved or angled. 



Leaves broadly oval, contracted into margined petioles. 4. 5. ftexicaulis. 



Leaves lanceolate, sessile. 5. S. Curlisii. 



2. Heads 2"-3" high, chiefly in a terminal spike-like thyrsus; achenes glabrous, or nearlyso. 

 Rays white; stem pubescent. ' ^ . . 



Raj'S yellow; stem densely pubescent. 

 Rays yellow; stem glabrous, or sparingly pubescent. 



Leaves thick, not acuminate, dentate, or the upper entire. 

 Leaves thin, acuminate, sharply serrate. 



3. Heads 5"-6" high; bracts elongated, acute; leaves ovate. 

 ^ Heads in a terminal simple or branched thyrsus, not at all secund on 



I . Bracts of the involucre acute. 

 High northern; leaves spatulate, glabrous. 



Eastern; stem minutely puberulent or glabrous; heads 2!="-3" high. 

 Western; stem and leaves scabrous or rough-pubescent. 



2. Bracts of the involucre obtuse (or the inner acutish in No. 13). 

 (a) Upper leaves abruptly smaller than the lower, appressed. i^. S. slricla. 

 (b) Leaves gradually smaller upward, spreading or ascending, 

 t Lower leai'es large, oblong or oz'ai, acute or obtusisli. 

 X At least the lowest leaves dentate; plants ^"-(f high. 

 Lower leaves oblong-lanceolate; branches of the thyrsus appressed. 14. .S. tiligiitosa. 



Lower leaves ovate or broadly oval; branches of the thyrsus ascending. 15 S. specinsa, 



% X Leaves lanceolate or oblong-lanceolate, entire, I'-j' long. 16. 5. rigidiuscula. 

 t t Basal leaves narroicly spatulate. 17. S. Purshii. 



t t t Basal leaves ohovate, oblanceolate, or bioadly spatulate. 

 Plant V-12' high, on alpine summits; stem angular. 18. S. alpeslris. 



Plant I °-3° high, not alpine; heads 3"-4" high. 19. 5. I'irgaurea. 



^ ^ ^ Heads in a terminal, usually large panicle, secund on its spreading or recurved branches. 

 J Plant maritime; leaves thick, fleshy, entire. 20. S. seiiipervirens. 



XX Plants not maritime ; leaves not fleshy. 

 I. Leaves pinnately-veined. not triple-nerved. 



(a) Leaves all entire, thin and glabrous. 21. S. odora. 



6. S. bicolor. 



7. 5. hispida. 



8. S. erecta. 



9. S. luonticola. 

 10. 5". inacroptiylla. 



its branches, or scarcely so. 



44. 5*. multtradiata. 



w. S. puberula. 



12. 5. I.indheimeriana. 



