AMBROSIACKAR. •■!'-i9 



1. Gaertneria acanthocarpa (Hook.) Britton. (Franscria Hookeriana 

 Null.) On plains and in sandy valleys from Sask. and B. C. to Tex. and 

 Calif. — Alt. 4000-8000 ft. — Colorado Springs ; Denver ; Mucrtano Valley, near 

 Gardner; lUiena Vista; (Jrand Junction; Delia; Rocky Ford; Grand River. 



2. Oaertneria tenuifolia (A, (iray) Kunlzc (Pranseria Icnuifolia A. Gray) 

 In nioisl Kri'und from Kans. and Colo, to 'lex. and ('alif. ; also in Mcx. — 

 Exact locality not given. 



3. Gaertneria linearis Rydb. Dry plains of Colo. — Alt. about 7000 ft. — 

 Calhan. 



4. Gaertneria tomontosa (Nnlt.) Heller. (Ambrosia tomentosa Nutt. ; 

 Pranseria discolor Nutt.) In dry s(5il from S. D. and Wyo. to Kans. and 

 N. M.— Alt. 40oo-<5ooo ft. — I'lailc River; i'"i. Collins; New Windsor; Boulder. 



5. Gaertneria Grayl Heller. {Pranseria tomentosa A. Gray) River val- 

 leys in- K.-ms., Neb, and Eastern Colo. — Exact locality not given. 



6. XANTHIUM L, Cocklebur. 



I. Xanthium commune Britton. In valleys from Que. and N. Y. to Utah and 

 Ariz. -Ft. Collins. 



I'amily 133. CARDUACEAE Necker. Thistle Family. 



Stit'iiiiilie liiiea at the base of the stigmas or below the middle; heads always 

 discoid, never yellow or brown; anthers not caudate at the base. 

 Stigma filiform or subulate, hispidiilous. Tribe i. Vernoniae. 



Stigmas more or leas clavate, papillose-puberulent. Tribe i. Eupatoriae. 

 Stigmatic lines extending to the tips of the stigmata or to the appendage thereof, 

 if present. 

 Anther-sacs not tailed al the base ; heads most commonly radiate and with 

 yellow or brown disk-flowers. 

 Stigm.'ila of the perfect flower.s with more or less distinct appendages; these 

 usually strongly hairy outside, glabrous inside, but never with a ring 

 of longer hairs. Tribe 3. Astereae. 



Slignuila of the perfect flowers without appendages; or if with appendages, 

 lliesc hairy on botli sides and with u ring of longer hairs. 

 Pappus never capillary ; stigma rarely appendaged. 

 Bracts of the involucres herbaceous or foliaceous. 



Receiitacle with chalTy scales, subtending the flowers. 



Tribe 5. Heliantheae. 

 lU-cc|ilac1e naked, or in Gaillardia with bristles, but not chafl:y-bractcd. 



Tribe 6. Heleniae. 

 Bracts of the involucres dry and scarious. Tribe 7. Anthemideae. 



Pappus capillary ; stigma often appendaged. Tribe 8. Senecioneae. 



Anther-sacs ciciclnle at the base; heads never radiate and corollas yellow only 

 in a few species of Carduus. 

 Anthers not appendaged at the top; heads heterogamous or dioecious; pis- 

 tillate flowers with filiform corollas. Tribe 4. GNArHAUAE. 

 Anther with elongated cartilaginous, mostly caudate appendages at the top; 

 flowers all hermaphrodite or the marginal neutral; corolla not filiform. 



Tribe 0. Cynaheae. 



TuniK I. VERNONIAE. 

 One genus. '• Vernonia. 



Tride 2. EUPATORIAE. 



Aohenes 5-nnKled without intervening ribs; pappus of wholly capillary bristles, 



mostly uniaerial. 2. Eupatorium. 



Achenes 8-io-ribbed or 8- lo-atriate. 



