248 COMPOSITE. ■ Oxyterm. 



78. OXYT]±3NIA, Nutt. ('Ofw-evi??, pointed, "in allusion to the rigid 

 narrow foliage.") — PL Gamb. 172; Benth. & Hook. Gen. ii. 353; Gray, Bot. 

 Calif, i. 343. — Single species, Artemisia-like in habit ; fl. autumn. 



O. acerosa, Nutt. 1. c. Shrubby, but soft-woody, 3 to 5 feet high, canescent, with erect 

 branches sometimes leafless and rush-like : leaves when present alternate, pinnately 3-5-parted 

 into long filiform divisions, or uppermost entire : heads numerous (2 lines long), in dense 

 panicles. — Dry plains, S. W. Colorado to S. E. California, Gambel, Wheeler, Brandegee, &c. 



79. DIC6RIA, Torr. & Gray. (At's, twice, used for two, and Kopis, a bug, 

 from the aspect of the two akenes of the original species.) — Emory Rep. 143, & 

 Bot. Mex. 86, t. 30 ; Gray, Proc. Am. Acad. xi. 76, & Bot. Calif, i. 615. 



D. oanescens, Torr. & Gray, 1. u. Herb a foot to a yard high, with annual root, stem 

 becoming liguescent at base and widely branched, herbage canescent with appressed pubes- 

 cence and the branches hispid, becoming green and scabrous in age : lower leaves opposite, 

 lanceolate and oblong, coarsely toothed or laciniate ; upper alternate, ovate or roundish, all 

 petioled : beads sparsely and irregularly racemose-paniculate, along slender nearly leafless 

 branchlets, nodding in fruit : fertile flowers 2 : inner bracts of the involucre pelatoid-scarious 

 (yellowish white), orbicular and deeply concave, accrescent in fruit (becoming 3 or 4 lines 

 long), then inflated-saccate and loosely or partly enclosing the laciniately wing-margined 

 akene, falling with it. — Desert washes, S. E. California and adjacent Arizona to S. Utah. 



D. Brand.6gei, Gray, 1. c. Strigulose-canescent, diffusely and alternately branched (base 

 of stem unknown) : leaves of the branches oblong-lanceolate or partly spatulate, obtuse, 

 mostly entire, an inch or less long and with slender petiole : heads sparse, racemose-panicu- 

 late; some all male: corollas sparsely hirsute: fertile flower solitary; its dilated-cuneate 

 hyaline subtending bract hardly accrescent or surpassing the outer involucre : akene naked 

 and exserted, bordered with pectinate callous teeth connected by an indistinct scarious mar- 

 gin. — Sandy bottoms of the San Juan, near the boundary between Colorado and Utah, 

 Brandegee. Little Colorada, N. Arizona, Rusby, in flower only. 



80. HYMENOCLfiA, Torr. & Gray. ('Y/^v, membrane, used for wing, 

 and /cAetu), to enclose.) — Two known species, of low and much branched shrubby 

 plants, minutely canescent, or else glabrous and smooth; with slender diffuse 

 branches, bearing profuse scattered or glomerate paniculate small heads, the two 

 sexes intermixed, or the female in lower axils : leaves all alternate' and linear-fili- 

 form; the lower sparingly and irregularly pinnately parted: fl. summer and 

 autumn. — PI. Fendl. 79 ; Gray, PI. Wright, i. 104, Bot. Calif, i. 343. 



H. Salsola, Torr. &.Gray, 1. c. Fructiferous involucre fusiform, strobilaceous ; the ample 

 orbicular silvery-scarious wings spirally alternate, imbricated over each other, radiately 

 spreading when mature and dry. — Torr. PI. Eremont (Smiths. Contrib.) 14, t. 8. — Saline soil 

 in the desert region, S. California, adjacent Arizona, and Nevada; first found by Fremont. 



H. monogyra, Torr. & Gray, 1. c. Fructiferous involucre smaller (2 lines long), winged 

 only at the middle by a whorl of obovate or rhombic-reniform radiating scales of smaller 

 size. — S. California through Arizona to S. W. Texas ; first coll. by Coulter. (Adj. Mex.) 



81. AMBROSIA, Tourn. Ragweed. (Ancient Greek and also Latin 

 name of several plants, as well as of the food of the gods.) — Weedy or coarse 

 herbs ; with mostly lobed or dissected opposite and alternate leaves, and dull in- 

 conspicuous flowers ; in summer. Sterile heads racemose or spicate, and with 

 no subtending bracts ; the fertile below, commonly in small clusters in the axils 

 of leaves or bracts : fl. summer and autumn. — Lam. 111. t. 765 ; Gasrtn. Fruct. 

 t. 164; Schk. Handb. t. 292; Torr. & Gray, Fl. ii. 354. — Fructiferous nut-like 

 involucre called for shortness "fruit." 



