Dysodia. COMPOSITE. 355 



* * Perennial (as to N. American species), with narrow entire sessile leaves, glaucescent, much 

 branched, 1 to 3 feet high. 



P. gracile, Bextii. Lignescent at base, with slender striate branches: odor pungent, "Fen- 

 nel-like " : leaves nari-uwly linear with tapering base, or uppermost filiform or subulate, or all 

 filiform : involucre cylindraceous, half-inch long ; its bracts 5, oblong or linear-oblong, obtuse, 

 scarious-margined, often slightly purple-tinged: corollas dull white and purple, with tube as 

 long as the narrowisli throat and short triangular-lanceolate lobes : akenes attenuate at apex, 

 ratlier longer than the papjnis. — Bot. Sulph. 29 ; Gray, Bot. Calif, i. 399. P. Gregijii, Gray, 

 PI. Wright, i. 120, in part, & ii. 94. — Arid plains, S. W. Texas to San Diego Co., California. 

 (Lower Calif., Adj. Mex.) 



P. SCOparium, GnAV. Shrubby at base, with slender rush-like liranches: leaves thick and 

 firm, liuear-subuLite and filiform, narrow at base, mucronate-apiculate : involucre campanu- 

 late, 4 or 5 lines high, of 7 to 9 broadly lanceolate greenish bracts, one third to half shorter 

 than the mature pappus : corollas yellow, with very short obtuse teeth, and narrow throat 

 much longer than the proper tube (i. e. below the insertion of the stamens) : akenes not at- 

 tenuate at apex, fully ecjualled by the pappus. — PL Wright, i. 120, ii. 94, & Proc. Am. Acad, 

 xviii. 108. P. Gre(/(jii, Gray, PI. Wright. 1. c, as to pi. Gregg, a stouter form. — Kocky 

 banks and plains, S. W. Texas and New Mexico; first coll. by Wright. W. borders of 

 Texas, Havard. (Adj. Mex.) 

 P. AJiPLEXiCAULK, Engclni. in PI. Wright. 1. c, of adjacent Mexico, is stouter, less branched, 



with solitary and lai-ger heads, and fleshy-coriaceous leaves lanceolate, tapering from a partly 



clasping base, all but the uppermost opposite : bracts of the involucre 8 to 10, half-inch long. 



164. CHRYSACTlNIA, Gray. (Xpuo-09, gold, .Ikti?, ray, from the 

 golden yellow rays, which distinguish the genus from the preceding.) — PI. Fendl. 

 93, & PI. AVright. i. 119. — Single species, with resinous-aromatic odor. 



C. Mexicana, Gray, 1. c. Fruticulose, about a foot high from a stout base, mucii branched, 

 very leafy: leaves alternate. Heath-like, thick or almost terete, short-linear or filiform, with 

 narrowed base, cuspidate-mucronate, entire, with abundant round oil-glands : heads on slen- 

 der peduncles terminating the branches, a third of an inch high : bracts of the involucre 

 lanceolate, liardly longer than the akenes, usually bearing a single large and prominent 

 infra-apical oil-gland : disk-corollas with short proper tube and long cylindrical throat (in 

 the way of PorophijUum scoparium and P. amplexicaulr) : akenes shorter than the pappus. — 

 Rocky ground, W. Texas and adjacent New Mexico ; first coll. by Gregg. (Mex.) 



165. NICOLLIETIA, Gray. (Memory of /. N. Nicollet, astronomer and 

 explorer of the region between Upper Mississippi and Missouri Rivers.) — Per- 

 ennial herbs ; with alternate leaves irregularly pinnately parted, and leafy branches 

 terminated by large heads of purple or liesh-colored Howers, or disk-corollas at first 

 yellow. — Rep. Fremont 2d Exped. olo, PI. AVright. i. 119, & Bot. Calif, i. 398. 



N. OCCidentalis, Gray, 1. c. Stout, somewhat fleshy, a foot or two high : branches leafy 

 uj) to the head : leaves with numerous or several short lanceolate-subulate or linear setosely 

 tipj)ed lobes: involucre three-fourths inch long, of 8 to 12 bracts: ligules oblong, little sur- 

 passing the disk. — Sandy banks and plains of the Mohave Desert region, S. E. California; 

 first coll. liy Fremont, who made his earliest exploration under Nicollet. 

 N. Edwardsii, Gray. More slender, a span or two high : leaves attenuate-linear, few- 

 ^ lobed : heads somewhat naked-pedunculate : involucre turliinate at base, half-inch long, of 

 8 or 9 bracts: ligules much exserted, elongated-oblong, dentate or denticulate at the truncate 

 summit, commonly inilf-incli long. — PI. Wright, i. 119, t. 8, & Bot. Mex. Bound. 93. — 

 Sandy banks and plains, S. W. Texas and adjacent New Mexico, Bigclow, Parry. (Adj. 

 Mex., Dr. Edwards, Pal mar. Lower Calif., Streets.) 



166. DYSODIA, Cav., as Dijssodia. (Aucrw^ta, an ill smell.) — Herbs or 

 suffrutescent plants, of N. America and Mexico, mostly strong-scented ; with 

 alternate or opposite leaves, and solitary or rarely somewhat paniculate heads of 



