AMBROSIACEAE. 329 



1. Gaertneria acanthocarpa (Hook.) Britton. {Franseria Hookeria)ia 

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

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

 Gardner ; Buena Vista ; Grand Junction ; Delta ; Rocky Ford ; Grand River. 



2. Gaertneria tenuifolia (A. Gray) Kuntze. (Franseria tenuifolia A. Gray) 

 In moist ground from Kans. and Colo, to Tex. and Calif. ; also in Mex. — 

 Exact locality not given. 



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

 Calhan. 



4. Gaertneria tomentosa (Nutt.) Heller. {Ambrosia tomentosa Nutt.; 

 Franseria discolor Nutt.) In dry soil from S. D. and Wyo. to Kans. and 

 N. M. — Alt. 4000-6000 ft. — Platte River; Ft. Collins; New Windsor; Boulder. 



5. Gaertneria Grayi Heller. {Franseria tomentosa A. Gray) River val- 

 leys in Kans., 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. 



Family 133. CARDUACEAE Necker. Thistle Family. 



Stigmatic lines 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, hispidulous. Tribe i. Vernoniae. 



Stigmas more or less clavate, papillose-puberulent. Tribe 2. Eupatoriae. 

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

 if present. 

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

 yellow or brown disk-flowers. 

 Stigmata of the perfect flowers with more or less distinct appendages ; these 

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

 of longer hairs. Tribe 3. Astereae. 



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

 these hairy on both sides and with a ring of longer hairs. 

 Pappus never capillary ; stigma rarely appendaged. 

 Bracts of the involucres herbaceous or foliaceous. 



Receptacle with chaft'y scales, subtending the flowers. 



Tribe 5. Heliantheae. 

 Receptacle naked, or in Gaillardia with bristles, but not chaffy-bracted. 



Tribe 6. Heleniae. 

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



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



Anther-sacs caudate 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. Gnaphaliae. 

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

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



Tribe 9. Cynareae. 



Tribe i. VERNONIAE. 

 One genus. i. Vernonia. 



Tribe 2. EUPATORIAE. 



Achenes s-angled without intervening ribs ; pappus of wholly capillary bristles, 



mostly uniserial. 2. Eupatorium. 



Achenes 8-io-ribbed or 8-io-striate. 



