Vol.. III.] THISTLE FAMILY. 299 



Jf Anthers not tailed at the base ; stigmatic lines of the style-branches only at the base, or not extending 

 beyond the middle ; flowers all tubular and perfect, never yellow ; rays none. 



Style-branches filiform or subulate, hispidulous; receptacle naked. Tribe 1. Vernoxikai:. 



Style-branches thickened upward, obtuse, papillose. Tribe 2. Eupatorieae. 



X- -/- Anthers tailed at the base, unappendaged at the tip; heads small; rays none (except in Inula 



where they are large, yellow). Tribe 4. INULEAE. 



-X- -X- -a- Anthers not tailed at the base ; stigmatic lines of the style-branches in the perfect flowers 

 extending to the summit; flowers tubular only, or tubular and radiate, often yellow. 



1. Receptacle naked (see als Nos. 79, 80, 8i and 82 of Tribe 7.) 

 a. Bracts of the involucre usually well imbricated. 

 Style-branches of the perfect flowers flattened, with terminal appendages. Tribe 3. Astereae. 

 Style-branches truncate, or with hairy tips. Tribe 6. Helenieak. 



b. Bracts little imbricated, or not at all; pappus of soft bristles. Tribe 8. Senecioneae. 



2. Receptacle chaffy (except in Nos. 79, 80, 81 and 82). 



Bracts of the involucre herbaceous or foliaceous; not scarious. Tribe 5. Heliantheae. 



Bracts of the involucre dry, scarious. Tribe 7. Anthsmideae. 



-X- -X- -X- -X- Anthers long-tailed at the base, with elongated appendages at the tip; heads large; rays none. 



(in Centaurea often with enlarged marginal flowers; ; bracts imbricated. Tribe 9. CYXAREAE. 



Tribe i. Vernonieae. 



Pappus double, the inner of rough capillary bristles, the outer of scales, or short bristles; heads 



not glomerate. 1. Vernonia. 



Pappus a single series of bristles; heads glomerate, subtended by sessile bracts. 2. Elephantopus. 



Tribe 2. Eupatorieae. 



X- Achenes 3-5-angled, not ribbed. 

 Pappus of 5 broad obtuse scales; aquatic herb with linear whorled leaves. 3. Sclerolepis. 



Pappus of numerous capillary bristles. 



Involucre of more than 4 bracts; erect herbs. 4. Enpatorium. 



Involucre of 4 bracts; twining herbaceous vines. 5. Willughbaeya. 



X- -X- Achenes 8-10-ribbed, or 8-10-striate. 



1 . Bracts of the involucre in several series, the outer successively shorter. 

 Bracts of the involucre strongly striate-nerved; heads panicled or cormybed in our species. 

 Pappus-bristless rough or serrate; involucral bracts numerous. 6. Coleosanthus. 



Pappus-bristles plumose; involucral bracts few. 7. Kuhnia. 



Bracts of the involucre faintly striate, if at all; heads spiked or racemed. 8. Lacinaria. 



2. Bracts of the involucre in only 2 or 3 series; all nearly equal. 9. Trilisa. 



Tribe 3. Astereae. 



A. Ray-flowers yellow (white in one species of Solidago), or wanting; plants not dioecious. 

 X- Pappus of scales, or awns, or wanting, never of numerous capillary bristles. 

 Heads small, not over 2" high; leaves narrowly linear, entire. 



Perennial herbs, or shrubs; all the flowers fertile. 10. Gulierrezia. 



Annual herb; disk-flowers sterile. 11. Amphiachyris. 



Heads large, showy; leaves oblong to lanceolate, spinulose-dentate. 12. Grindelia. 



-X- -X- Pappus of either the radiate or tubular flowers, or both, of numerous capillary bristles, with or 



without an outer series of shorter ones, or of scales. 



t Pappus, at least of the disk-floivers, double, an inner series of capillary bristles, and an outer 



one of scales or short bristles; heads large. 

 Achenes of the ray- flowers thick, the pappus obsolete, or of a few caducous bristles; achenes of 



the disk-flowers flat. 13. Heterotheca. 



Achenes of both ray-flowers and disk-flowers flattened. 14. Chrysopsis. 



1 1 Pappus wholly of capillary bristles. 

 I . Heads wholly of disk-flowers (in our species); rays none; leaves narrowly linear. 



a. Perennial herbs; style-tips not exserted; eastern. 15. Chondrophora. 

 b. Shrubs; style-tips mostly exserted; western. 

 Involucral bracts gradually narrowed to the tip, keeled, chartaceous. 16. Chrysothamnus. 



Involucral bracts cuspidate, flat, herbaceous. 17. Oonopsis. 



2. Heads with both ray-flowers and disk-flowers (in our species). 

 a. None of the leaves cordate; pappus mostly as long as the achene, or longer. 

 Leaves bristly-serrate or pinnatifid. 



Achenes glabrous; pappus-bristles deciduous. 18. Prionopsis. 



Achenes white-tomentose; pappus-bristles persistent. 19. Eriocarpum. 



Leaves entire, or toothed, not bristly-serrate. 



Leaves narrow, coriaceous, evergreen, entire; low western undershrubs. 20. Stenotus. 

 Annual or perennial herbs; leaves not evergreen. 



Pappus-bristles unequal; heads loosely panicled; annual. 21. Isopappus. 



Pappus-bristles equal; heads variously clustered; perennial herbs. 



Receptacle alveolate; rays mostly not more numerous than the disk-flowers. 



22. Solidago. 

 Receptacle fimbrillate; rays more numerous than the disk-flowers; heads corytnbose- 

 pamculate. 23. Euthamia. 



b. Lower and basal leaves cordate; pappus-bristles shorter than the achene. 24. Brachychaeta. 



B. Ray-flowers present, not yellow in any of our species. 

 % Pappus a mere crown, or of a few awns or bristles, or wanting, never of numerous capillary bristles. 



I . Receptacle conic. 

 Outer bracts of the involucre shorter than the inner; achenes prismatic. 25. Aphanostephus. 



Bracts of the involucre all about equal; achenes flattened. 26. Bellis. 



' 2. Receptacle flat, or somewhat convex. 



Achenes of the disk-flowers compre.-sed, of the ray-flowers 3-angled; perennial herbs with large 

 heads. 27. Toicnsendia. 



