CARDUACEAE. 295 



to triangular-ovate, 8-17 cm. long, with a somewhat square basal sinus, thin 

 but firm, with scattered hairs above, pubescent on the veins beneath, the teeth 

 rather coarse, sharp : upper stem-leaves with ovate-oblong to lanceolate blades 

 and short-winged petioles, or the uppermost ones sessile, acuminate: inflo- 

 rescence glabrous or sparingly pubescent, flattish or irregularly convex: heads 

 about 1 cm. high: peduncles rather long and slender: involucral bracts mostly 

 obtuse, green-tipped: ray-flowers about 10; ligules 8-11 mm. long, white or 

 pink. S. Occasional, in thickets along the Octoraro Greek. Schists. 

 Sum. 



4. A. macrophyllus L. Stems 6-9 dm. tall, reddened, angular: radical leaves 

 developed in large colonies, usually 3 to each rootstock, larger and coarser than 

 the similarly shaped lower cauline leaves (which are developed a subsequent 

 year from the same rootstock) ; blades broad, cordate with a large irregular 

 sinus, rough above, harsh, thick, the teeth broad, curved, somewhat crenate: 

 upper stem-leaves with oblong blades and short broadly winged petioles, those 

 of the uppermost sessile, acute: inflorescence strigose and glandular, broadly 

 corymbose, irregular: heads 15-30 mm. broad: peduncles short, rigid, thiekish: 

 involucral bracts conspicuously green-tipped, the outer acute, the inner oblong, 

 obtuse: ray-flowers about 12-16; ligules 10-14 mm. long, chiefly lavender, 

 sometimes violet, or rarely pale: disk turning reddish-brown. S. Occasional, 

 on wooded hillsides and in thickets. Schists. 



5. A. cordifolius L. Stems 3-15 dm. tall, glabrous or nearly so, much- 

 branched and bushy: leaf -blades thin, rough, more or less pubescent, sharply 

 serrate, acuminate, those of the basal and lower cauline leaves slender-petioled, 

 broadly ovate-cordate, 5-12 cm. long, those of the upper cauline leaves short- 

 petioled or sessile, ovate or lanceolate : heads very numerous, small, 12-18 mm. 

 broad, handsome: involucre turbinate to cylindric; bracts oblong-linear, obtuse 

 or obtusish, green-tipped, appressed: ray-flowers 10-20; ligules 6-8 mm. long, 

 blue or violet, sometimes pale, rarely white: pappus whitish. Common, in 

 woods and thickets. 



6. A. undulatus L. Stems stiff, 3-10 dm. tall, closely rough-pubescent, divari- 

 cately branched above: leaf -blades usually thick, rough on both sides when 

 dry, pubescent beneath, dentate, undulate or entire, acute or acuminate, those 

 of the radical leaves small, orbicular to ovate, soft-downy; the lower cauline 

 leaves ovate, with cordate base, 5-12" cm. long, the naked petioles expanding 

 into a clasping base at least in some leaves; middle cauline leaves similar, 

 lanceolate or oblong; upper cauline leaves sessile or clasping, chiefly lance- 

 oblong; branch-leaves subulate, small and abruptly reduced: heads numerous, 

 racemose and somewhat secund on the spreading branches, 16-20 mm. broad: 

 involucre broadly turbinate; bracts linear-oblong,, slightly pubescent, acute or 

 acutish, their broad green tips appressed: ray-flowers 8-15; ligules usually 

 pale-violet, 6-10 mm. long : pappus whitish. Common, on dry banks and in 

 woods. 



7. A. patens Ait. Stems 3-9 dm. tall, slender, rough, divergently branched: 

 leaf -blades sessile, ovate-oblong or oval, rough-pubescent, thick and somewhat 

 rigid, strongly auriculate-clasping at the broad base, entire, acute, or the 

 lower ones obtuse, 2.5-7.5 cm. long, those of the branches much smaller and 

 bract-like, their margins rough-ciliate : heads 25 mm. broad or more, solitary 

 at the ends of the branches: involucre campanulate; bracts linear-oblong, 

 finely pubescent or scabrous, often somewhat glandular, their green acute tips 

 spreading: ray -flowers 20-30; ligules purplish-blue or deep-violet, 8-12 mm. 

 long : pappus tawny. Common, in dry soil. 



8. A. phlogifolius Muhl. Similar to A. patens in habit but when well devel- 

 oped much taller, more slender and soft: leaves larger; blades lanceolate to 

 oblong-lanceolate, entire, thin or membranous, acuminate at the apex, strongly 

 auriculate-clasping at the base, roughish above, pubescent beneath, usually 



