352 FLOKA OF TEXAS. 



BIDEXS, L. Beggar-ticks. 



Chiefly like Coreopsis, but the exterior involucre ofteu 

 long and leaf-like; the achenia compressed, or 3-4 angled 

 (not narrowed at the apex), and crowned with 2-4 persist- 

 ent downwardly barbed or hispid awns ; leaves serrate, or 

 pinnately divided, opposite; rays yellow or white, often 

 ■wanting; Jis^• yellow. 



* Achenia flattened, narrowly wedge-shaped. 



B. FROXDOSA, L. Stem tall, branched ; leaves thin, long- 

 petioled, pinnately 3-5-divided, the divisions ovate or ovate- 

 lanceolate, acuminate, sharply serrate; heads discoid; ex- 

 terior scales of the involucre large, leafy; achenia 2-awned. 

 Stem 2°-5° high; margins of the achenia upwardly ciliate. 



B. CHRYSANTHE3I0IDES, Michx. Smooth ; stem erect or 

 ascending; leaves undivided, oblong-lanceolate, obscurely 

 serrate, connate ; heads radiate, showy; achenia 2-4-awned; 

 annual. Stem thick, l°-2° high. 



** Achenia Z-A-aiigled, linear ; heads radiate ; scales of the involucre nearly equal. 



B. BIPIXXATA, L. Stem tall, 4-angled, much branched ; 

 leaves bipinnate, the divisions small, ovate or lanceolate, 

 acute; heads small; rays 2-3, yellow; achenia 3-4 awned; 

 annual. Stem 2°-5° high. 



YERBESmA, L. 



Heads many-flowered; scales of the involucre in 2 rows, 

 imbricated; ray-floicers few, sometimes none; receptacle 

 flat, or somewhat convex, tlie chafi" concave; achenia wing- 

 less, 2-awned, laterally compressed ; stems winged by the 

 decurrent lobed or serrated leaves; heads corymbose; 

 flowers white or yellow. 



y. SiEGESBECKiA. Stem 4°-6° high, 4-winged, branch- 

 ing; leaves lanceolate-ovate, acuminate, serrate, opposite, 



