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 adi air pi ee 
. N. altissimus. 
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. 
eaf-blades merely toothed or somewhat incised. 
Larger bracts of the outer involucre lanceolate: lower leaf-blades ob- 
long to oval. not cordate. . N. integrifolius. 
Larger bracts of the outer involucre ovate: lower leaf-blades hastate, 
cordate. 4. N. Roanensis. 
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- 
e 
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. N. 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 altissimus (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 em. 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 mm. thick; inner bracts narrowly linear, glabrous: ligules 
greenish or yellowish : achenes slender, 4-5 mm. long: pappus light straw-colored. 
[ Prenanthes altissimus L.] 
In woods and on hillsides, Newfoundland to Manitoba, Georgia and Tennessee. Summer and fall. 
2. Nabalus Albus (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 integrifólius 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 mountairi slopes or in woods, New York to North Carolina and Georgia. Latesummer and fall. 
4. Nabalus Roanénsis 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 serpentàrius (Pursh) Hook.  Perennial, glabrous or nearly so. Stems 
3-10 dm. tall, branching vll the branches often widely spreading : leaf-blades 5-30 
cm. long, pinnately or hastately 3-7-lobed, narrowed into winged oe 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 trifoliàtus 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 gea leaves gradually less lobed, and on the 
upper part of the stem they are sometimes lanceolate and entire: heads 7-12-flowered, 
