Ziwnia. COMPOSITE. 25 



Q 



§ 2. Leaves attenuate to both ends and short-petioled ; their axils triply spi- 

 niferous. — § Acanthoxanthium, DC. 



X. spin6sum, L. A foot or two high, much branched : leaves ovate-lanceolate with cuneate 

 base, the larger 3-lobed or incisely pinnatifid, glabrate and green above, white-tomentose 

 beneath ; axils bearing long and slender 3-parted yellow spines : fertile involucres solitary 

 or few in upper axils, cylindraceous, half-inch long, obtuse, armed with short weak prickles, 

 inconspicuously 1-2-beaked or pointless. — Lam. 111. t. 655, f. 4; DC. 1. c. — A weed of 

 S. Atlantic States and Pacific coasts, occasionally about seaports northward to Massachusetts. 

 (Nat. from Trop. Am.) 



84. Zf NNIA, L. (Dr. J. G. Zinn, of Gottingen, who figured the original 

 species as a Rudbeckia.) — American, chiefly Mexican, herbs or suffruticulose 

 plants ; with opposite and mostly sessile entire leaves, single heads terminating 

 the branches, and showy flowers, the brightrcolored rays long enduring : fl. sum- 

 mer.— Gen. ed. 6, 437 ; Gsertn. Fruct. t. 172 ; Gray, PI. Wright, i. 105. Zinnia 

 & Diplothrix, DC. Prodr. v. 534, 611. 



§ 1. Etjzinnia. Herbs, mostly annual (some species perennial) : leaves from 

 ovate to linear : ray-flowers several or numerous, usually without pappus. — PI. 

 "Wright. 1. c. 



Z. pauciflora, L. Erect annual : leaves from lanceolate to oblong-ovate, commonly with 

 subcordate base, scabrous : peduncle sometimes enlarging and hollow : involucre narrow- 

 campanulate : ligules from obovate to narrowly spatulate, red, purple, or yellow : akenes of 

 the disk 1-awned, sometimes with a rudiment of a second awn or tooth. — Webb, Spic. 

 Gorg. 141. Z. pauciflora & Z. multiflora, L. Spec. ed. 2, 1269 (L. f. Dec. t. 12). Z, tenui- 

 flora, Jacq. Ic. Rar. t. 590, with narrow ligules. Z. revoluta, Cav. Ic. iii. 251. Z. leptopoda 

 & probably Z. bicuspis, DC. Prodr. v. 535. Z. intermedia, Engelm. Bot. Wisliz. 23. — Lou- 

 isiana to Texas, but probably introduced, Arizona, apparently indigenous. (Mex., S. Am., 

 and now widely dispersed.) 



§ 2. Diplothrix. Suffruticulose and tufted perennials: leaves narrow and 

 rigid, connate-sessile, usually crowded : ray-flowers commonly few, and their 

 akenes 2-4-aristate : head conspicuously pedunculate only in Z. juniperifolia. — 

 PL Wright. 1. c. Diplothrix, DC. 



# Ligules shorter than or little surpassing the disk, sometimes wanting : stems mainly herbaceous. 

 — § Heterogyne, Gray, PI. Wright. 1. c. 



Z. anomala, Gray. Scabrous-hispid : stems or branches very numerous from a ligneous 

 base and root, 4 to 8 inches high : leaves linear (half-inch to inch long, less than 2 lines 

 wide), one-nerved, obscurely 3-nerved at base : peduncle shorter than the uppermost leaves : 

 involucre oblong or campanulate (half-inch long) : ligules 4 to 6, oval or oblong, 1 to 3 lines 

 long, yellow or orange, occasionally the whole corolla wanting : hispid style-branches of the 

 disk-flowers acuminate-subulate. — PI. Wright, i. 106, t. 10, & ii. 86. — S. W. Texas, Wright. 

 (Mex. near Saltillo, Palmer, with broader involucre.) 



* # Ligules (4 or 5) ample, dilated-obovate or roundish, at maturity much surpassing the disk, 

 light yellow or sulphur-color, becoming white in age : involucre narrow : stems or branches a 

 span or more high from the stout woody base or branching caudex. 



Z. grandiflora, Nutt. Scabro-hispidulous : leaves linear, 3-nerved at base : involucre 

 usually 4 lines long : ligules at maturity 5 to 8 lines long : style-branches of the disk-flowers 

 attenuate-subulate. — Trans. Am. Phil. Soc. n. ser. vii. 348 ; Torr. & Gray, PI. ii. 298 ; Torr. 

 in Emory Rep. t. 4 (style incorrect) ; Gray, 1. c. — Plains and bluffs, E. Colorado to S. W. 

 Texas and Arizona, 



Z. plimila, Gray. Cinereous-puberulent : leaves very narrowly linear (hardly half-line 

 wide, half-inch or less long), one-nerved : involucre 2 or 3 lines long, and ligules 2 to 4 lines : 

 style-branches of disk-flowers with short triangular-subulate tips. — PI. Eendl. 81, PI. Wright. 

 1 c. — High plains and table-lands, S. W. Texas to Arizona. (Adj. Mex.) 



