outer phyllaries long, green, much-surpassing the disk or else subequal; rays about 



1 cm. long; ray flowers fertile, yellow, showy, deeply 3-toothed terminally; wings 

 of the achene rarely narrow or nearly vestigial, usually broad and acutish sum- 

 mitally. Ximenesia encelioides Cav. and var. cana DC, X. australis H. & A., X. 

 exauriculata (Robins. & Greenm.) Rydb. 



Very frequent in disturbed soils, especially common on floodplains and out- 

 washes of winter streams, essentially throughout our region, summer; Fla., Tex., 

 s.e. through most of the warmer parts of Am., adv. in Old World. 



32. Calyptocarpus Less. 

 A monotypic genus. 



1. Calyptocarpus vialis Less. Hierba del caballo. 



Perennial herbs, with weak often sprawling stems (1-) 2-6 dm. long but only 

 2-9 cm. tall; leaves opposite, with deltoid marginally serrate strigose blades 1-3 

 (-4) cm. long and petioles (or subpetiolar winged bases) about a third as long; 

 peduncles naked, axillary, 3-50 mm. long, topped by a solitary head; head less 

 than 1 cm. long; involucre obconical; phyllaries about 5, slightly unequal (the 

 inner ones shorter and narrower), leaflike in texture, obtuse and broadly over- 

 lapping; receptacle chaffy throughout, the scarious pales lance-subulate; ray 

 flowers pistillate, fertile, the yellow rays spatulate; disk flowers perfect, fertile, the 

 yellow corollas equally 5-toothed; achenes strongly dorsiventrally compressed, 

 subulate; pappus of 2 awns, one over each corner of the achene. Zexmenia 

 hispidula Buckl. 



Frequent in low wettish woods, on edge of water of streams and sloughs, s.e. 

 Tex. and Rio Grande Plains, infrequent n. to e. and n.-cen. Tex. and Edwards 

 Plateau, nearly all year; Pan., C.R., Guat. and Mex., n. to Coah., Tex., La., Ala. 

 and Fla.; Cuba. 



A troublesome lawn weed. 



33. Coreopsis L. Coreopsis. Tick-seed 



Annual or perennial herbs, glabrous or pubescent; leaves opposite or more rarely 

 (in the upper part of the plant) alternate, undivided and entire or dentate, or 1 to 

 3 times ternately or pinnately dissected; heads peduncled; phyllaries commonly in 



2 or rarely in 3 or 4 series, more or less connate at the very base (but not high 

 up); outer phyllaries commonly herbaceous or submembranous and appressed or 

 often spreading; inner bracts commonly larger, brown or yellow, membranous; 

 receptacle flat or slightly convex, chaffy throughout; pales flat or somewhat con- 

 cave, membranous, striate; ray flowers present, neuter or pistillate, usually in- 

 fertile; rays spreading, yellow (in some species with two shades of yellow, in 

 others with a red-brown spot basally), 3-toothed terminally; disk florets numerous, 

 perfect and fertile, the corolla yellowish (often with reddish veins) and equally 

 5-toothed terminally; achenes dorsiventrally flattened, orbiculate to oblong or 

 more or less oblong-linear, often 2-winged (the wings membranous or indurate- 

 thickened, entire or not, flat or incurved), glabrous or especially at the margin 

 villous; pappus usually present, usually of 2 awns over the two shoulders of the 

 achene and with or without intermediate scales, persistent. 



A genus of probably 100 species widely distributed. 



\. Achenes wingless, narrowly oblong, slender flattish L C. tinctoria. 



\. Achenes winged (2) 



2(1). Achenial wings entire 2. C cardaminaefolia. 



2. Achenial wings dissectedly fimbriate-pectinate 3. C. linifolia. 



1660 



