§ 1. Scales of the involucre more or less unequal, all but the innermost terminating
in subulate and spinose spreading appendages: leaves decurrent.
(Eriolepis, Cass.)
1. C. lanceolatum (Scop.): stem branching, somewhat hairy; leaves decurrent
on the stem and forming a spinose lobed wing, pinnatifid, rough and
bristly^ above, somewhat glabrous or arenose-woolly beneath ; the lobes and
teeth tipped with spines and with spinulose margins; involucre ovoid, nearly
bractless, arachnoid; the scales linear-lanceolate, tipped with spines, the exterior
spreading; flowers purple. DC. ! prodr. 6. p. 636.—Carduus lan-
ceolatus, Lin n .; Engl. bot. t. 107 ; FI. Dan. t. 1173 ; HooJc. ! fl. Bor.-Am.
1 . p. 302; Darlingt.! Jl. Cest. p. 436. Cnicus lanceolatus, Willd. ; Pursh,
fl. 2. p. 506; Bigel. fl. Bost. ed. 2. p. 292.
Pastures and road-sides throughout the Northern and Middle States ! introduced
from Europe. Also Newfoundland, (Hook., DC.) June-Sept.—(D
Common Thistle.
§ 2. Scales of the ovoid or globose involucre either mucronate or tipped with
a prickle; the innermost always unarmed: filaments hairy. (Onotrophe,
Cass.)
* Scales of the involucre closely appressed and regularly imbricated in numerous series,
the outermost very short, the others successively elongated, all but the innermost tipped
with aspreading or recurved acicular prickle (leaves not decwrrent, canescently tomen-
tose beneath).
2. C. Pitcheri: canescently tomentose throughout; stem stout, very leafy,
simple or sparingly branched; leaves all pinnately parted, rigid; the segments
narrowly linear, elongated, with revolute margins, terminated with
small prickles, entire, or sparingly and remotely pinnately parted; heads
usually several, racemose-spicate in the axils of the upper leaves; scales of
the globose involucre oblong-lanceolate, acuminate, with arachnoid margins,
appressed, tipped with a small spreading prickle; flowers ochroleucous.—
Cnicus Pitcheri, Torr. in Eaton, man. ea. 5. p. 180.
On the sand banks of Lake Superior, Lake Huron, &c. Dr. Pitcher!
Shore of Lake Michigan, Dr. Wright! June-July.— 'll? A foot or more
high. Lower leaves 6—8 inches long, with a rigid narrowly margined rachis,
which is naked at the base; the segments numerous, 1-4 inches long, 1-2
lines wide. Heads an inch in diameter, terminal, and on very short leafy
branches in the axils of the upper leaves. Corolla nearly regular. Filaments
somewhat pubescent. The longer bristles of the plumose pappus obscurely
thickened at the summit.
3. C. undulatum (Spreng.): canescently tomentose throughout; stem low,
angled, often branched above; the branches leafy, bearing solitary (pretty
large) heads; leaves lanceolate-oblong, partly clasping, sinuate-pinnatifid,
plicate-undulate, very while and tomentose beneath; the lobes often incised
or 2-cleft, spinose; scales of the subglobose involucre lanceolate, appressed;
the exterior tipped with a small and weak spreading prickle; the inner with
attenuated membranous lips; flowers reddish-purple.—DC. prodr. 6. p. 651.
C. Douglasii, DC. prodr. 6. p. 643 ; Nutt.! in trans. Am e r. phil. soc.
1. c .p . 419. Carduus undulatus, Nutt.! gen. 2 .p. 130.
j3. smaller and more slender; leaves more spinose and deeply pinnatifid.
Calcareous Islands of Lake Huron, and Upper Missouri, Nuttall! Hills
of the Missouri near Fort Pierre, Mr. Nicollet! (a. & (3.) Oregon, Douglas
(probably not California, as given by De Candolle), Nuttall! June-July.—
© I Plant 1-2 feet high. Radical leaves sinuate and less spinose. Scales
of the involucre at length almost glabrous, often glutinous along the midrib.
4. C. Hookerianum (Nutt.): arachnoid-tomentose throughout; stem simple
or sparingly branched at the summit; striate; leaves lanceolate or linear,
sinuate-pinnatifid, with the lobes often toothed or incised,, spinulose, arachnoid
above, canescently tomentose beneath;' the cauline somewhat clasping;
heads (rather small) 2—5, subsessile; scales of the subglobose very woolly
involucre lanceolate, erect, tipped with somewhat spreading prickles ; the innermost
unarmed; flowers apparently purple.—Nutt.! in trans. Amer. phil.
soc. 1. c. p. 418. Carduus discolor (in part), Hook. ! fl. Bor.-Am. 1. p. 302.
Saskatchawan or Rocky Mountains? (Richardson or Drummond.)—Plant
12-16 inches high, slender: doubtless distinct from C. discolor; but the specimens
are not very complete. The stronger bristles of the pappus are somewhat
more evidently clavellate or thickened at the apex than in most other
species.
5. C. discolor (Spreng.): stem striate, hirsute, with leafy somewhat spreading
branches; leaves all deeply pinnatifid, sessile, sparsely hairy and green
above, densely tomentose-canescent (bluish-white) beneath; the segments
divaricate, mostly 2—3-lobed, lanceolate or linear-lanceolate, spinulose-ciliate,
and tipped with an acicular prickle; scales of the globose involucre somewhat
arachnoid, appressed; the exterior ovate and tipped with a very slender
spreading acicular prickle; the innermost linear-lanceolate; flowers reddish-
purple.— Spreng. syst. 3.p . 373; DC. prodr. 6. p. 640. Cnicus discolor,
Muhl.! in Willd. spec. 3. p. 1670; Ell. sk. 2. p. 271; Bigel. fl. Bost. ed.
2. p. 292. Carduus discolor, Nutt. gen. 2. p . 130; Darlingt.! fl. Cest. p.
437. Serratula discolor, Poir.
Fields and along thickets, (Canada?) Northern and New England States!
to Illinois! Kentucky! and the upper districts of S. Carolina. July-Sept.
— © Stem 3-6 feet high ; the rather slender branches leafy to the summit,
and terminated by heads an inch or more in diameter. Leaves of the
branchlets quite small; the lower cauline 6—12 inches long (the white persistent
tomentum very closely appressed) ; the segments mostly long and narrow,
often falcate.
6. C. altissimum (Spreng.): stem tall, pubescent or somewhat woolly,
branching; the branches leafy to the summit; leaves roughish-pubescent
above, densely tomentose-canescent beneath, spinulose-ciliate; the radical
petioled, pinnatifid; the cauline sessile, oblong-lanceolate, either undivided,
sinuate-toothed, or sinuate-pinnatifid; the lobes or teeth spinescent; heads
(rather large) bracteate; scales of the globose-ovoid involucre arachnoid
when young, appressed ; the exterior ovate-lanceolate, tipped with a spreading
acicular prickle; the innermost narrow, with scarious acuminate tips ;
flowers mostly purple.—DC. ƒ prodr. 6. p. 640, fynot. 8. pi. rar. Genev. p . 5.
C. altissimum, laciniato folio, Sec., Dill. Elth. 1 . p. 81, t. 69. C. diversi-
folium, DC.! prodr. 1. c. p. 649. Carduus altissimus, Linn. spec. 2. p . 824 ;
Nutt. gen. 2. p. 129; Darlingt. fl. Cest. p. 439. Cnicus altissimus, Willd.
spec. 3. p. 1671 ; Ell. sk. 2. p. 268.
Fields and thickets, Pennsylvania! and Ohio! to Western Missouri!
Louisiana! Alabama! Carolina! &c. Aug.-Sept__21 ? Stem 3-10 feet
high. Leaves quite variable in outline ; sometimes the radical undivided :
when the cauline are pinnatifid, the lobes are usually few and short, oblong
or triangular. Scales of the involucre with a livid line or spot near the apex,
which is often somewhat glutinous. Heads about an inch in diameter.
7. C. Virginianum (Michx.): stem slender, simple or loosely branched
above, arachnoid; the branches or peduncles nearly naked; leaves sessile,
von. n.—58