254 COMPOSITE. Zinnia. 



Z. acerosa, Gray. Cinereous-pubescent or glabrate : leaves acerose-filiform, very obscurely 

 one-nerved, half-inch or more long : ligules 3 to 6 lines long : style-branches with subulate- 

 ovate tips. — PI. Wriglit. 1. c. Lliplothiix acerosa, UC. Frodr. v. 611.— Hills, S. W. Texas, 

 Wright. (Adj. Mex.) 



85. SANVITALIA, Lam. {Sanvitali, name of a noble Italian family.) 

 — Mostly low and branching herbs, of Mexico and its border ; with opposite and 

 more or less petioled leaves, almost always entire, and rather small heads termi- 

 nating the branches, ours and most of the species annuals. — .Jour. Hist. Nat. 

 ii. (179-2), 176, t. 33 ; 111. t. 686; Cav. Ic. iv. 31, t. 351 ; DC. Prodr. v. 628. 

 Lorentea, Ort. Dec. iv. 42, t. 5. 



§ 1. Involucre of 2 or 3 series of bracts, their tips commonly herbaceous: 

 fructiferous receptacle from flat to strongly conical ; its chaffy bracts soft or 

 shorter than the flowers : disk commonly dark purple or brownish : rays yellow 

 or turning whitish in age : ray-akenes mostly triangular ; the comparative smooth- 

 ness, granulation, or murication of disk-akenes inconstant. 



■ S. ocymoides, DC. A span or two high, diffusely spreading, hispidulous or hirsute: 

 leaves oval, obtuse, abruptly contracted into the petiole : ligules shorter than the akene and 

 shorter than the three slender-subulate diverging awns : disk-akenes all wingless, quadran- 

 gular-compressed, sometimes 1-2-awned. ^ S. ocymoides & S. Iragicefolia, DC. 1. c. — South- 

 ernmost border of Texas on the llio Grande, Berlandier, Schott. (Adj. Mex.) 

 S. PEOCITMUENS, Lam. 1. c. (.S'. villosa, Cav. Ic. 1. c), a Mexican species not uncommon in 

 cultivation, has conspicuous ligules much exceeding the awns at their base, and flattened disk- 

 akenes, some of them ^^'inged and 1-2-aristellate, some not ; and the receptacle, at first barely 

 convex, may become even acutely conical iu age. ^. acinifolia, DC. 1. c, appears to be only 

 a form of it. 



S. AXGUSTir6LiA, Engelm. in Gray, PI. Wright, i. 112, of Northern Mexico, has similar 

 akenes and similar receptacle, but rays nearly as short as those of !i. ocymoides ; the chaff of 

 the receptacle disposed to be rigid-tipped as in the following. 



§ 2. Involucre a single series of drj' bracts : fructiferous receptacle strongly 

 and acutely conical ; its chaffy bracts conspicuous and with rigid cuspidate tips : 

 rays white : disk pale : lea^'es rarely denticulate. 



-8. Aberti, Geay. , Erect, at length a foot high, with ascending branches, minutely pubescent 

 or hispidulous, glabrate : leaves lanceolate or nearly linear, 3-nerved, narrowed into a mar- 

 gined petiole : rays 1 to 3 lines long : akenes all corky-thickened ; those of the ray almost 

 terete, narrowly 4-sulcatc, bearing 3 very short and stout nearly conical awns or tubercles ; 

 of the disk compressed-ijuadrangular, wingless, awnless, or sometimes minutelv uniaristeUate. 

 — PI. Feudl. 87, & PI. Wright, i. 111. — S. W. Texas, New Mexico, and S. Arizona. 



86. HELI6PSIS, Pers. ("HAtos, the sun, oi//ts, likeness, from resemblance 

 to the Sunflower.) — American perennials (or a Mexican and South American 

 species annual) ; with loosely branching stems, ovate or oblong and veiny mostly 

 serrate S-ribbcil or triple-ribbed leaves, on naked petioles, and ]iedunculate showy 

 heads; the rather numerous rays yellow, and the disk yellowish. Fl. summer 

 and autumn. — Syn. ii. 473; Torr. & Gray, Fl. ii. 302; Benth. & Hook. Gen. 

 ii. 3.5.4. 



H. Iffivis, Pf.rs. Smooth and glabrous or nearly so throughout, 3 or 4 feet high : leaves 

 bright green, thinnish, oblong-ovate or ovate-lanceolate from a truncate or sliglitly cuneate- 

 decurrent liase, acuminate, ci.arsdy and sliarply serrate with numerous teeth (.3 to 5 inches 

 long) : heads somewhat cmTmbose : rays broadly linear, an inch long, at length niarcescent 

 and decaying auay : akenes wholly glabrous and smooth, the summit wliollv truncate or oli- 

 scurely 2-4-toothed. — Pursli, PI. ii. 5G3 ; Duual, Mem. Mus. v. 55 ; Hook. Bot. Maij. t. 3372 ; 



