4 2I 



Genus 63.] THISTLE FAMILY 



i. Borrichia frutescens (L,.) DC. Sea 

 Ox-eye. (Fig. 3897.) 



Buphihalmum frutescens L- Sp. PL 903. 1753. 

 Borrichia frutescens DC. Prodr. 5: 488. 1836. 



Finely canescent, even when old; stems terete, spar- 

 ingly branched, i-4 high. Leaves mostly erect or 

 ascending, spatulate or obovate, obtuse or acutish and 

 mucronulate at the apex, fleshy, tapering to the sessile 

 base, somewhat connate, x'-jf long, 2 // ~7 // wide; 

 heads solitary or few, about 1/ broad; rays 15-25, 

 rather short; exterior bracts of the involucre ovate 

 and somewhat spreading, the inner ones and the chaff 

 of the receptacle cuspidate. 



Sea-coast, Virginia to Florida and Texas. Also on the 

 coasts of Mexico and the West Indies. April-Oct. 



64. HELIANTHUS I,. Sp. PI. 904. 1753. 

 Erect, annual or perennial, mostly branched herbs, with opposite or alternate, simple 

 leaves, and large peduncled corymbose or solitary heads of both tubular and radiate flowers, 

 the rays yellow, the disk yellow, brown, or purple. Involucre hemispheric, or depressed, its 

 bracts imbricated in several series. Receptacle flat, convex or conic, chaffy, the chaff sub- 

 tending the disk-flowers. Ray-flowers neutral (in our species), the rays spreading, mostly 

 entire. Disk-flowers perfect, fertile, the corolla tubular, the tube short, the limb 5-lobed. 

 Anthers entire, or minutely 2-toothed at the base. Style-branches tipped with hirsute ap- 

 pendages. Achenes thick, oblong or obovate, compressed, or somewhat 4-angled. Pappus 

 of 2 scales or awns, or sometimes with 2-4 additional shorter ones, deciduous. [Greek, sun- 

 flower.] 



About 60 species, natives of the New World. Besides the following, about 18 others occur in 

 the southern and western parts of North America. 



-jfr Disk purple, purplish or brown; receptacle flat or convex. 



1 . Leaves mostly alternate, the lower opposite. 

 Leaves narrow,' linear or lanceolate; perennials. 



Stem rough; leaves linear or linear-lanceolate; eastern. 

 Stem glabrous; leaves elongated-linear; western. 

 Leaves broad, ovate; annuals. 



Leaves dentate; bracts ovate, acuminate, ciliate, hispid. 

 Leaves entire or nearly so; bracts lanceolate, canescent. 



2. Leaves mostly opposite, the upper alternate. 

 Leaves hispid, abruptly contracted into winged petioles. 

 Leaves gradually narrowed into petioles. 



=f -7T Disk yellow^or yellowish; receptacle convex or conic, 

 t Leaves nearly all basal or ?iear the\base; upper bract-like. 



7. H. occidentalis. 

 1 1 Stems leafy; leaves alternate or opposite. 

 1. Leaves prevailingly lanceolate and 3-8 times as long as wide. 

 a. Leaves glabrous on both sides; heads i'-\ l A' broad. 



b. Leaves scabrous, at least on the upper surface. 

 Heads %'-\%' broad; leaves thin; stem glabrous. 

 Heads 1%'-^%' broad; leaves firm, many of them often alternate. 

 Stem scabrous, scabrate or hispid; leaves sessile or nearly so. 

 Leaves lanceolate, scabrous above, hirsute beneath. 

 Leaves elongated-lanceolate, very scabrous on both sides. 

 Stem glabrous; leaves sessile by a truncate base. 

 Stem glabrous, glaucous; leaves petioled. 



2. Leaves prevailingly ovate, ovate-lanceolate, or oblong. 

 a. Leaves sessile, or very nearly so. 

 Stem glabrous; leaves divaricate. 

 Stem hirsute or hispid; leaves ascending. 

 Leaves cordate-clasping at the base. 

 Leaves narrowed from below the middle. 



b. Leaves manifestly petioled. 

 Stem puberulent or glabrous. 



Leaves membranous, slender-petioled, sharply serrate. 

 Leaves firmer, shorter-petioled, less serrate or entire. 

 Bracts of the involucre much longer than the disk. 

 Bracts of the involucre about equalling the disk. 

 Stem hirsute, hispid, or scabrous. 



Leaves rounded or truncate at the base, short-petioled. 

 Leaves, at least the upper, narrowed at the base 



Bracts of the involucre ovate-lanceolate, appressed. 



1. H. angustif otitis. 



2. H. orgyalis. 



9- 



10. 

 11. 



T 3 

 12. 



13- 



14. 

 15- 



H. annuus. 

 H. petiolaris. 



H. atrorubens. 

 H. scaberrimus. 



H. laevigatas. 

 H. microcephalus. 



H. gi^anleus. 

 H Maximiliani. 

 H. divaricatus.'.. 

 H. grosse-serratus. 



H. divaricatus. 



H. mollis. 



H. doronicoides. 



16. H. decapelalus. 



17. 



H. tracheliifolius. 

 II. strumosus. 



19. H. hirsutus. 



20. H. laetiflorus. 



