AMBROSIACEAE. 329 



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

 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 chaffy 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. 



