298 COMPOSITE. Bidens. 



merely spreading : rays oval (in ours half-inch long, in Mexican sometimes an inch) : disk 

 in fruit only 4 lines high, comparatively broad : outer akenes narrowly cuneate-oblong and 

 only 2 lines long, innermost 3 lines long and cuneate-linear, apex not attenuate : awns 2, 

 strongly barbed, of half or a third the length of the akene. — Bot. Reg. t. 684 (1822) ; DC. 

 Prodr. v. 603 ; Gray, Proc. Am. Acad. xix. 16. B. fceniculifolia, DC. 1. c. (probably) ; Gray, 

 PI. Wright, ii. 90 ; Rothr. Wheeler Rep. vi. 165. B. ferulozfolia, Hemsl. Bot. Biol. Centr.- 

 Am. ii. 202, mainly, not Jacq. — Arizona, Wright, Thurber, Lemmon. (Mex.) 



# # # Leaves some undivided, some 3-5-parted into lanceolate or linear divisions: root perennial. 



B. heteroph^lla, Ort. Glabrous or nearly so, often tall : leaves of firm texture and with 

 ascending veins, mostly serrate with erect teeth, from oblong to lanceolate and tapering into 

 a petiole, sometimes all undivided, commonly some 3-parted or the upper 5-parted into lan- 

 ceolate or linear lobes : heads in flower 3 and in fruit about 5 lines high : rays broadly ob- 

 ovate, half to three-fourths inch long, deep yellow : akenes cuneate-linear, the inner (3 lines 

 long) little longer than the outermost, 2-3-awned. — Dec. 99, t. 12; DC. Prodr. v. 597. B. 

 arguta, HBK. Nov. Gen. & Spec. iv. 231 ; DC. 1. c. B. longifolia, DC. 1. c. — S. Arizona, 

 along streams, Pringle, Lemmon. (Mex.) 



Var. Wrightii. Base of stem and lower leaves unknown : upper leaves and (when 

 divided) their divisions lanceolate-linear, entire or nearly so, the longer A or 5 inches long 

 and 3 or 4 lines broad. — PI. Wright, ii. 90 (as unnamed doubtful var.); Rothrock in 

 Wheeler Rep. vi. 165. — S. Arizona, Wright, Rothrock, Lemmon. Seemingly an extreme 

 form of a variable species. 



§ 3. HydrocakpJja. Akenes almost terete, cartilaginous, truncate at both 

 ends, bearing 3 to 6 very long and rigid acerose awns, which are smooth below, 

 the upper part densely and retrorsely hispidulous : aquatic : submersed leaves 

 filiformly dissected : rays conspicuous, yellow. 



B. Beckii, Torr. Submersed stems much elongated in deep water, thickly beset with the 

 almost capillary ternately multifid leaves ; emersed summit bearing a few pairs of oblong- 

 lanceolate serrate leaves, or the lower pinnatifid : head short-peduncled : bracts of the invo- 

 lucre oblong : rays obovate, over half-inch long : mature akenes half-inch and the rigid 

 diverging awns an inch or less long, very persistent. — Torr. in Spreng. Neu. Entd. ii. 1 35, 

 Syst. iii. 455, & PI. N. Y. i. 388, t. 58. — In slow-flowing streams and ponds, Canada to New 

 Jersey and Missouri ; first coll. by L. C. Beck. 



1 14. C6SMOS, Cav. (Koo-^o?, an ornament.) — Tropical American herbs, 

 chiefly Mexican, too near Bidens; for there is one yellow-rayed species, and 

 certain species with purple rays have hardly a beak to the akenes. — Ic. i. 9, 

 t. 14, 79; DC. Prodr. v. 606; Benth. & Hook. Gen. ii. 387. Cosmea, Willd. 

 Spec. iii. 2250. 



C. CAUDAirns, HBK. Apparently annual: leaves twice pinnately parted into lanceolate acute 

 lobes : rays rose-colored, seldom much surpassing the involucre : akenes fusiform, with beak 

 longer than the body (in all nearly inch long), 2-awned. — HBK. Nov. Gen. & Spec. iv. 240 ; 

 Torr. & Gray, Fl. ii. 349. — Key West, Blodgett. (Evidently introduced from W. Ind.) 



C. eipinnatos, Cav. 1. c. t. 14. Annual: leaves pinnately divided into narrowly linear or 

 almost filiform lobes : heads very showy, the deep rose-colored rays commonly an inch or 

 more long : akenes smooth and glabrous throughout, with abrupt beak very much shorter 

 than the body, or in some flowers reduced to a mere neck : awns 1 to 3, short (Mexico) ; in 

 var. exaristAtus, DC 1. c, the awns wholly wanting. — The var., S. Texas, near Maria, on 

 an abandoned ranch (base of stem becoming lignescent), Havard. (Mex.) 



C. parviflorus, HBK. Annual, slender : heads smaller, with either white or rose-colored 

 rays half to a quarter of an inch long : beak of the akenes slender, usually half the length 

 of the body, scabrous, 2-3-awned: otherwise as preceding, into which it may pass. — 

 Nov. Gen. & Spec. iv. 241. C. bipinnatus, var. parviflorus, Gray, PI. Wright, ii. 90. Coreopsis 

 parvi flora, Willd. Spec. iii. 2551. Bidens Humboldtii, Schultz Bip. in Bot. Herald, 307.— 

 S. W. Texas to Arizona. (Mex.) 



