1370 CARDUACEAE 
XX. ERYNGIIFOLII 
Heads sessile and subremote in the upper axils. 98. A. spinulosus. 
Heads terminal, solitary or clustered. 99. A. eryngiifolius. 
XXI. TENUIFOLII 
Ligules of the ray 5-7 mm. long: heads 4—6 mm. high. 100. A. Bracei. 
Ligules of the ray 10—20 mm. long: heads 6-8 mm, high. 
Involucral bracts broad: ligules of the ray violet: . 
leaves chiefly basal. 101. A. Chapmani. 
me bracts linear: ligules of the ray pale-violet "NM 
r nearly white: leaves scattered. 102. A. tenuifolius. 
X . SUBULATI 
Involucre campanulate to broadly bun. 
Inner bracts of the involucre 5—6 m . long, acuminate : . 
rays fewer than the disk flowers. 103. A. exilis. 
Inner bracts of the involucre 3— 5 mm. long, acute or 
Short acuminate: rays more numerous than the disk- 
flower 04. A. inconspicuus. 
Involucre cylindric to narrowly turbinate. 105. A. subulatus. 
XIII 
A rush-like, much branched plant with scattered, white- : 
rayed heads of flo owers, the stem and branches a a 106. A. spinosus. 
A. divaricatus L. Stems tufted, 4-6 dm 1, flexuous, brittle, terete, 
giabrate: leaf, blades thin, smoothish, pat pK ovate- Hd elosely 
arp eeth, 
e sa u ME 
ately large, broad and deep: leaves of the 
infloresence D c 
E d ovate-aeute to short-oval, nearly 
orymb 
green spot: dis ddish b = 2 
Rich woodlands and bap a rather dry ` 
soil, various provinces, Ga. to Ala., Man., 
and N. S.—Fall. 
2. A. tenebrosus Burgess. Stem glabrate, striate, wide-branched: leaf- 
blades A very thin and smooth, broadly elliptie and a cut with 
coarse re acuminate curvescent teeth, then abruptly long-acuminate and 
entire; Eon Teaves with a broad rounded sinus and slender petiole; is of the 
in nflorescence prolonged, lanee B e onim and sessile: inflorescence broadly 
- 2 mbose, oft e prolifero E branched: rays usually 9—12: disk pale-yellow, 
ing pu rplish-brown: ou bracts green, acute, elongate-triangular, the 
ae linear, obtusish. ae ree places, Blue Ridge and more N prov- 
inces, N. C. to Ohio and Mass.—Late —fall.—Resembles A. divaricatus, but 
rm in being ieee and thinner in all its parts, and in having a different Teaf- 
for 
= fe M pile idus Burgess. Stem greenish, slender, weak and often 
e 
elliptic e long-acuminate, with jode base and short petioles, and 
closely set with conspicuous sharp s traight- -backed tooth some lower leaves 
broader, ovate-acuminate with mode ie sinus and with double- curved o or couch- 
ant teeth; axile leaves divaricate, straight-tapere Es a sessile truncate base, 
everywhere closely slit-toothed, suggesting a barbed stiletto: Hii ne 
