CICHORIACEAE 1311 



columnar, terete or 5-angled, often 10-ribbed, truncate. Pappus of numerous hair-like 



rather rigid pale or brown bristles. Rattlesnake-root. White Lettuce. 



Bracts of the involucres glabrous or sometimes with a few scattered hairs. 



Involucres slender, about 2 mm. thick, 5-7-flowered, light green : pappus light straw-colored. 



1. N. alHssimus. 

 Involucres stout, 3-6 mm. thick, 8-16-flowered. deep green, glaucous or purple. 



Pappus deep cinnamon-colored. 2. N. albus. 



Pappus straw-color or light brown. 



Leaf-blades merely toothed or somewhat incised. 



Larger bracts of the outer involucre lanceolate : lower leaf-blades ob- 

 long to oval, not cordate. 3. N. integrifolius. 

 Larger bracts of the outer involucre ovate : lower leaf-blades hastate, 



cordate. 4. N. Eoanensis. 



Leaf-blades, at least some of them pinnatifid, lobed or divided. 

 Inflorescence paniculate. 



Panicles much broadened upward : bracts of the involucres, at least 

 the longer ones, glabrous. 

 Larger bracts of the outer involucre lanceolate : pappus surpass- 

 ing the inner involucral bracts. 5. N. serpentarius. 

 Larger bracts of the outer involucre ovate, or triangular-ovate : 



pappus and inner involucral bracts about equal in length. 6. N. trifoliatus. 



Panicles cylindric : bracts of the involucres sparingly hairy. 7. JS\ cylindricus. 



Inflorescence raceme-like. 8. N. virgatus. 



Bracts of the involucres copiously pubescent. 



Involucres 8-16-flowered : inflorescence thyrsoid. 9. N. asper. 



Involucres 20-25-flowered : inflorescence corymbose-paniculate. 10. N. crepidineus. 



1. Nabalus altissimas (L.) Hook. Perennial, glabrous or nearly so, not glaucous. 

 Stems erect, 1-2 m. tall, narrowly branched above : leaf-blades thin, usually light green, 

 5-15 cm. long, the lower usually hastately 3-5-lobed on long slender petioles, the upper has- 

 tate, deltoid, ovate or oblong-lanceolate, more or less strongly dentate, rounded or cordate 

 at the base or those of the inflorescence attenuate below : involucres 5-7-flowered, slender, 

 10-12 mm. long, about 2 ram. thick ; inner bracts narrowly linear, glabrous : ligules 

 greenish or yellowish : achenes slender, 4-5 mm. long : pappus light straw-colored. 

 \_Prenanlhes altissimus L.] 



In woods and on hillsides, Newfoundland to Manitoba, Georgia and Tennessee. Summer and fall. 



2. Nabalus ^Ibus (L. ) Hook. Perennial, glabrous or nearly so, often glaucescent. 

 Stems erect, 3-16 dm. tall, narrowly branched above, finely ridged in age : leaf-blades del- 

 toid, triangular or sometimes broader than long, more or less deeply hastate ; segments 

 lobed or dentate : involucres 10-12 mm. long ; outer bracts triangular to lanceolate, the 

 inner linear, glabrous or puberulent : ligules dull white or cream-colored : achenes about 

 5 mm. long : pappus cinnamon or cinnamon-brown. \_Prenanthes alba L.] 



On banks or in woods, Maine to Ontario, Manitoba, Georgia and Kentucky. Summer and fall. 



3. Nabalus integrifolius Cass. Perennial, hirsute or glabrate. Stems 4-18 dm. 

 tall, more or less branched above, the branches often sharply ridged : leaf-blades oblong, 

 varying to oval-oblong or oblong-lanceolate, sometimes slightly sagittate at the base, sinu- 

 ate or sinuate-dentate, more or less abruptly narrowed into winged petioles or the upper 

 sessile : involucres 11-15 mm. long ; inner bracts linear, bristly-hirsute or glabrate : 

 achenes 4.5-5 mm. long : pappus dirty brown. 



On mountain slopes or in woods, New York to North Carolina and Georgia. Late summer and fall. 



4. Nabalus Roan^nsis Chickering. Perennial, more or less hirsute. Stems erect, 

 3-5 dm. tall, topped by a narrowly cylindric panicle : leaf-blades triangular-hastate to 

 hastate-lanceolate, 3-10 cm. long, acuminate, dentate or incised and dentate, pale beneath, 

 truncate to cordate at the base ; petioles as long as the blades, or shorter : involucres 8-10 

 mm. long; inner bracts linear, more or less hirsute: achenes 4-4.5 mm. long: pappus 

 dingy straw-colored. 



On the summit of Roan Mountain, North Carolina, and on neighboring peaks. Summer and fall. 



5. Nabalus serpentarius (Pursh) Hook. Perennial, glabrous or nearly so. Stems 

 3-10 dm. tall, branching above, the branches often widely spreading : leaf-blades 5-30 

 cm. long, pinnately or hastately 3-7-lobed, narrowed into winged petioles or the upper ses- 

 sile ; lobes toothed or incised : involucres 10-12 mm. long ; outer bracts mostly lanceolate, 

 occasionally pubescent ; inner bracts linear, glabrous: achenes 4.5—5 mm. long : pappus 

 straw-colored. [Prenanthes serpentaria Pursh.] 



In open woods, fields or thickets, Ontario to Florida, Kentucky and Alabama. Summer and fall. 



6. Nabalus trifoliatus Cass. Perennial, deep green, glabrous. Stems erect, 8-26 

 dm. tall, more or less widely branching above : leaves various ; blades thinnish, those of 

 basal and lower stem-leaves 1-3 dm. long, usually 3-divided, long-petioled ; segments lobed 

 or toothed, sessile or stalked : blades of the upper leaves gradually less lobed, and on the 

 upper part of the stem they are sometimes lanceolate and entire : heads 7-12-flowered, 



