]248 CARDUACEAE 



77. CRASSINA Scepin. 



Annual or perennial caulescent herbs or shrubby plants. Leaves opposite : blades 

 commonly narrow, entire or sparingly toothed. Heads radiate, often showy. Involucres 

 campanulate or somewhat cylindric : bracts in 3-4 series, firm, appressed, rather dry. Re- 

 ceptacle conic or cylindric, chaffy. Ray-flowers pistillate, fruit-producing : ligules red, 

 purple or yellow, or variegated. Disk -flowers perfect, fruit-producing, enveloped in the 

 bractlets. Stigmas of the disk-flowers truncate or subulate. Achenes various ; those of 

 the ray 3-angled ; those of the disk flattened. Pappus of one or several awns or teeth, or 

 wanting. [Zinnia L.] 



Annual : leaves few : achene usually with 1 awn : ray-flowers conspicuous. 1. C. Peruviana. 



Perennial : leaves numerous : achene with 2-4 awns : ray-flowers with ligules shorter 



than the disk, or these wanting. 2. C. anomala. 



1. Crassina Pemviana (L. ) Kuntze. Stems 1-6 dm. tall, finely pubescent or gla- 

 brous, often branched. Leaf-blades linear-oblong to ovate, 2-5 cm. long, acute, entire, 

 sessile : peduncles somewhat club-shaped : heads showy : involucres cylindric-campanu- 

 late, 1-1.5 cm. high ; bracts ovate to oblong, obtuse, glabrous, the tips barely spreading : 

 ray-flowers several ; ligules linear to oblong-spatulate, 1-1.5 cm. long, red, purple or yel- 

 low, thickish : bractlets of the disk nearly linear, 1.5 cm. long, eroded at the apex : achenes 

 nearly linear, 1 cm. long, glabrous. [Zinnia pauciflora L.] 



In dry soil, Louisiana to Texas and Arizona. Also in Mexico and South America. 



2. Crassina antfmala (A. Gray) Kuntze. Stems 5-18 cm. tall, scabrous-pubescent, 

 often much branched at the base. Leaf-blades linear, 1-2 cm. long, acute, entire : peduncles 

 shorter than the subtending bracts : heads not showy : involucres cylindric, 10-12 mm. 

 high ; bracts suborbicular to oblong, obtuse, ciliate, the inner ones only at the apex : ray- 

 flowers 4-6 ; ligules yellow or orange, 2-6 mm. long, or wanting : achenes 5-6 mm. long, 

 pubescent, each with a short and long awn, and sometimes with other rudimentary ones. 



In dry soil, Texas. Summer. 



78. SANVITALIA Lam. 



Annual, or rarely perennial, caulescent herbs, low or spreading in habit. Leaves 

 opposite : blades flat, mostly entire, petioled. Heads radiate, seldom showy. Involucres 

 broad and shallow : bracts in 1-3 series, dry or somewhat herbaceous. Receptacle flat, or 

 becoming somewhat elevated, chaffy. Ray-flowers pistillate, fruit-producing : ligules of ten 

 mucli reduced. Disk-flowers perfect, the corollas with glabrous lobes. Stigmas with trun- 

 cate or capitate tips. Achenes various, all, or only the outer ones, with thick walls, those of 

 the ray usually 3-angled, with 3 rigid awns or horns, those of the disk flat or 4-angled, 

 with a pappus of 1 or 2 awns or teeth, or pappus wanting. 



Bracts of the involucre in 2-3 series. 1. S. ocymoides. 



Bracts of the involucre in 1 series. 2. S. Abertii. 



1. Sanvitalia ocymoides DC. Stems usually branched at the base, the branches 

 erect or spreading, 1-4 dm. long, hirsute or hispid. Leaf-blades oval, ovate or elliptic, 

 1-2 cm. long, entire, commonly abruptly contracted at the base : involucres campanulate, 

 about 5 mm. high ; bracts mostly oblong, cuspidate, ciliate, in 2 or 3 series : ray -flowers sev- 

 eral ; ligules yellow, about 2 mm. long : disk-corollas 1.5 mm. long : achenes 3 mm. long ; 

 those of the ray glabrous, with 3 rigid spines ; those of the disk pubescent, spineless or 

 nearly so. 



In woods or thickets, southern Texas and adjacent Mexico. 



2. Sanvitalia Abe~rtii A. Gray. Stems 1-4 dm. tall, simple or sparingly branched, 

 hispidulous or glabrate. Leaf-blades almost linear to lanceolate, 1.5-5 cm. long, repand 

 or nearly entire, narrowed into margined petioles : involucres hemispheric, about 5 mm. 

 high : bracts firm, ovate-oblong to oblong-lanceolate, acute, in 1 series : ray-flowers sev- 

 eral ; ligules 3 mm. long : disk-corollas about 2 mm. long : achenes 3 mm. long ; those of 

 the ray nearly terete, with 3 stout spines ; those of the disk 4-sided, tuberculate, each 

 sometimes with a tubercle-like spine. 



In dry soil, Texas to Arizona. 



79. HELIOFSIS L. 



Perennial, or rarely annual, caulescent herbs. Leaves opposite : blades broadest below 

 the middle, toothed, petioled. Heads radiate, showy, solitary or in open corymbs. Invo- 



