CARDUACEAE 1263 



1. Borrichia frut6scens (L. ) DC. A somewhat fleshy branching shrub 2-7 dm. tall, 

 the young foliage pale-tomentose. Leaf-blades linear-spatulate to obovate, 2-6 cm. long, 

 cuspidate, entire or spiny-toothed especially near the base : heads rather conspicuous, on 

 stout club-shaped peduncles : involucres about 1.5 cm. broad ; bracts various, the outer 

 with merely acute herbaceous spreading or reflexed tips, the inner with rigid subulate 

 spreading tips : ray-flowers few ; ligules about 1 cm. long. 



On sandy seashores and in salt marshes, Virginia to Florida and Texas. Summer and fall. 



2. Borrichia arbor6scens (L. ) DC. A branching shrub 2-12 dm. tall, with silky- 

 canescent foliage. Leaf-blades oblanceolate or spatulate-oblanceolate, 3-6 cm. long, with 

 dark rigid cuspidate tips, entire, densely silky, sessile : heads not conspicuous, on club- 

 shaped peduncles : involucres 1.5-2 cm. broad ; bracts various, the outer keeled, acute, 

 appressed at maturity ; the inner larger, rounded at the apex : ray-flowers few ; ligules 6-8 

 mm. long. 



In salt marshes and on sandy beaches, peninsular Florida and the Keys. Also in the West Indies. 



3. Borrichia glabr^ta Small. A branching shrub 1-2 m. tall, with glabrous foliage. 

 Leaf-blades spatulate to linear-oblanceolate, 3-6 cm. long, entire, each with a rigid cuspi- 

 date tips : heads hardly conspicuous, on somewhat club-shaped peduncles : involucres 8-12 

 mm. broad ; bracts various, the outer keeled, obtuse, the inner broader, with minute cusps : 

 ray-flowers few ; ligules 6-8 mm. long. 



On sandy coasts and in salt marshes, southern Florida and the Keys. 



95. VIGUlisRA H.B.K. 



Perennial caulescent herbs or shrubby plants. Leaves opposite, or usually opposite on 

 the lower part of the stem and alternate above : blades broadest at the base, toothed or in- 

 cised. Heads slender-peduncled. Involucre campanulate to hemispheric, more or less 

 flattened in age : bracts narrow, in few series. Receptacle more or less convex, chaffy. 

 Ray-flowers neutral : ligules yellow. Disk -flowers perfect, fruit-producing ; corollas usually 

 yellow. Stigmas with slender tips. Achenes flattened, commonly pubescent. Pappus of 

 a chaffy awn or scale over each prominent angle of the achene and occasionally 1 or 2 more, 

 with 2 or several scales between them, persistent or deciduous. 



1. VigTiiera helianthoides H.B.K. Stem 6-20 dm. tall, often widely branched 

 above, glabrous or sparingly pubescent, often purple or purple-tinged : leaf-blades triangular 

 or ovate, 9-14 cm. long or shorter above, serrate, sometimes saliently and irregularly so, 

 scabrous above, abruptly narrowed, truncate or cordate at tiie base, petioled : heads quite 

 numerous : involucres about 1 cm. broad during anthesis : bracts lanceolate, abruptly nar- 

 rowed above the middle, 4-6 mm. long: ligules of the ray-flowers oblong to elliptic, 1-1.5 

 cm. long: achenes 3.5-4 mm. long. 



In dry soil and thickets, Texas to Arizona and Mexico. 



96. HELIANTHUS L. 



Annual or perennial caulescent herbs. Leaves alternate or opposite : blades simple, 

 entire or toothed. Heads conspicuous. Involucres flat, hemispheric or cylindric : bracts 

 in several series, fleshy or leathery. Receptacle flat, convex or conic, chaffy. Ray-flow- 

 ers neutral : ligules yellow. Disk-flowers perfect, fruit-producing : corollas brownish or 

 purple. Stigmas with pubescent appendages. Achenes flattened or somewhat 4-angled. 

 Pappus of 2 awns or scales, and these sometimes accompanied by 2-4 shorter ones, all early 

 deciduous. The plants flower in the summer and fall, unless otherwise stated. Sunflower, 



Plants annual : receptacle flat or nearly so. 



Stem branched at the base, the branches weak, diffusely spreading or decumbent. 

 Branches green : ligules of the ray-flowers mostly less than 1.5 cm. long. 



Branches glabrous or a little scabrous : leaf-blades repand or shallowly and broadly toothed. 



1. H. debilis. 

 Branches hirsute : leaf-blades sharply or prominently toothed. 2. H. praecox. 



Branches purple-mottled : ligules of the ray-flowers mostly over 1.5 cm. long. 3. H. cucumerifolius. 

 Stem rigid and essentially erect. 



Foliage pubescent with silky wool, sometimes floccose in age. 4. H. argophyllus. 



Foliage hispid, hirsute or scabrous. 



Leaf-blades of a broad or narrowly ovate type. 



Bracts of the involucre not hirsute : leaf-blades oblong-lanceolate 



to ovate-lanceolate. 5. H. petiolarif. 



Bracts of the involucre hirsute : leaf-blades broadly ovate. 6. H. ammus. 



Leaf-blades of a linear or linear-lanceolate type. 7. H. Flnndanus. 



Plants perennial : receptacle convex or low-conic. 

 Disk of the head purple to brown. 



