CARDUACEAE. 299 



the involucre with few long hairs: llgules of the ray pink, purplish or rarely 

 •white : disk-corollas less than half the length of the larger iuvolucral bracts. — 

 ■Common, in fields and thickets. — Sum. — Daisy-fleabane. Sweet-scabious. 



4. E. ramosus (Walt.) B.S.P. Stems 2-10 dm. tall, appressed-pubescent: 

 blades of the basal leaves spatulate to oblong, shallowly toothed: bracts of the 

 involucre with many short hairs: ligules of the ray white or rarely pale-pink: 

 disk-corollas over half the length of the larger involucral bracts. — Common, 

 in fields and on roadsides. — Sum. — Daisy-fleabane. 



16. LEPTILON Raf . Annual or biennial herbs. Leaves alternate : blades 

 Jiarrow, entire or sparingly toothed. Heads several or numerous, inconspicu- 

 ously radiate or discoid. Involucres usually campanulate or cylindric, few- 

 flowered: bracts very narrow, the inner much longer than the outer ones. Eay- 

 flowers few: corollas with a very slender tube and a minute ligule. Disk- 

 -coroUas with a campanulate or a cylindraceous throat and a long tube: lobes 

 deltoid. Pappus of many brittle capillary bristles in 1 series. 



1. L. canadense (L.) Britton. Stems 3-20 dm. tall, paniculate above, gla- 

 brate or sparingly hirsute: leaf-blades spatulate to linear or nearly so, ciliate 

 near the base: longer bracts of the involucre 3-3.5 mm. long: disk-corollas 

 2.5-3 mm. long. — Common, in fields and waste places. — Sum. and fall. — 

 HoRSE-vTEED. Butter-weed. 



17. DOELLINGEEIA Nees. Perennial relatively tall herbs. Leaves 

 Alternate: blades relatively broad, veiny, entire or nearly so. Heads in a 

 terminal corymb. Involucres campanulate to hemispheric, several-many- 

 flowered : bracts various, the inner scarcely wider than the outer but much 

 longer. Eay-flowers few or several: corollas with a long tube and a white or 

 cream-colored ligule. Disk-corollas with a funnelform throat and a long tube: 

 ■lobes lanceolate. 'Pappus of 2 distinct series, the outer series of short bristles 

 or scales, the inner of elongate capillary bristles. — White-toppped aster. 



Ligules narrow, less than 2 mm. wide : achenes thick, ribless, less than 1 mm. wide : 

 involucre of rather lax slightly overlapping bracts 

 Involucral bracts acute or acutlsh, the inner linear, ciliate 



at the tip. 1. D. vmhrllnta. 



Involucral bracts obtuse, the inner oblong, ciliate. 2. D. humilis. 



Ligules broad, over 3 mm. wide : achenes much flattened, ribbed, 



over 1 mm. wide : involucre of firmer much overlapping bracts. 3. D. infirma. 



1. D. umbellata (Mill.) Nees. Stems 6-25 dm. tall, corymbose above: blades 

 of the upper leaves membranous, elliptic, usually narrowly so, or linear-lan- 

 ceolate, usually acuminate: inner bracts of the involucre 3-4 mm. long: pappus 

 soft. — N. S. Common, on shaded banks and in thickets. — Late sum. 



2. D. humilis (Willd.) Britton. Similar to D. timhellata in habit, but more 

 stocky: blades of the upper leaves shorter, firm, elliptic, ovate, or oval, acute: 

 inner bracts of the involucre 4-5 mm. long: pappus soft. — S. Occasional, in 

 swamps. — Schists. ■ — Fall. 



3. D. infirma (Michx.) Greene. Stems 4-12 dm. tall, often widely branched: 

 ■blades of the upper leaves elliptic to oval, varying to broadest above or below 

 the middle, short-acuminate: inner bracts of the involucre 3-4 mm. long: 

 disk-corollas 3-4 mm. long : pappus rigid. — S. Occasional, on dry banks. 

 Schists. — Late sum. 



18. lONACTIS Greene. Perennial low rigid herbs. Leaves alternate: 

 blades narrow, entire. Heads few in a corymb or rarely solitary, conspicu- 

 ously radiate. Involucres campanulate to turbinate, many-flowered: bracts 



