3. C. atripliciflia, L. (PALE INDIAN P.) Glaucous; stem terete (3--6 high); leaves _palmately veined and angulate-lobed_, the lower triangular-kidney-form or slightly heart-shaped, the upper rhomboid or wedge-form, _toothed_.--Rich woodlands, western N. Y. to Wisc., Minn., and southward. Aug.

4. C. tubersa, Nutt. (TUBEROUS INDIAN P.) Stem angled and grooved (2--6 high), from a thick or tuberous root; _leaves green both sides_, thick, strongly _5--7-nerved_; the lower _lance-ovate or oval_, nearly entire, tapering into long petioles; the upper on short margined petioles, sometimes toothed at the apex.--Wet prairies, etc., Ohio to Wisc., Minn., and southward. June.

77. ERECHTTES, Raf. FIREWEED.

Heads many-flowered; the flowers all tubular and fertile; the marginal pistillate, with a slender corolla. Scales of the cylindrical involucre in a single row, linear, acute, with a few small bractlets at the base.

Receptacle naked. Achenes oblong, tapering at the end; pappus copious, of very fine and white soft hairs.--Erect and coa.r.s.e annuals, of rank smell, with alternate simple leaves, and paniculate-corymbed heads of whitish flowers. (The ancient name of some species of Groundsel, probably called after _Erechtheus_.)

1. E. hieraciflia, Raf. (FIREWEED.) Often hairy; stem grooved (1--6 high); leaves lanceolate or oblong, acute, cut-toothed, sessile, the upper auricled at base.--Moist woods; common, especially northward, and in recent clearings that have been burned over; whence the popular name.

July--Sept.

78. aRCTIUM, L. BURDOCK.

Heads many-flowered; flowers all tubular, perfect and similar. Involucre globular; the imbricated scales coriaceous and appressed at base, attenuate to long stiff points with hooked tips. Receptacle bristly.

Achenes oblong, flattened, wrinkled transversely; pappus short, of numerous rough bristles, separate and deciduous.--Coa.r.s.e biennial weeds, with large unarmed and petioled leaves, and small solitary or cl.u.s.tered heads; flowers purple, rarely white. (Name probably from ???t??, _a bear_, from the rough involucre.)

A. LaPPA, L. Stout, 1--3 high; leaves roundish or ovate and mostly cordate, or lanceolate with cuneate base, smooth above, somewhat floccose-tomentose beneath, mostly sinuate-denticulate. (Lappa officinalis, _All._)--The several reputed species of the genus are scarcely distinguishable even as varieties. Var. MNUS, has rather small ovoid subracemose heads (about 8" broad), on short peduncles, glabrous or somewhat cottony, the inner scales somewhat purplish-tipped, equalling the flowers; leaves occasionally cut-toothed. By roadsides; very common.--Var. MaJUS, with broader (1') green and glabrous subcorymbose rather long-pedunculate heads. Less frequent.--Var.

TOMENTSUM, a form of the last with more spherical webbed heads, with purplish scales shorter than the flowers. Rare.--July--Oct. (Nat. from Eu.)

79. CNCUS, Tourn. COMMON or PLUMED THISTLE.

Heads many-flowered; flowers all tubular, perfect and similar, rarely imperfectly dicious. Scales of the ovoid or spherical involucre imbricated in many rows, tipped with a point or p.r.i.c.kle. Receptacle thickly clothed with soft bristles or hairs. Achenes oblong, flattish, not ribbed; pappus of numerous bristles united into a ring at the base, plumose to the middle, deciduous.--Herbs, mostly biennial, with sessile alternate leaves, often pinnatifid, p.r.i.c.kly. Heads usually large, terminal. Flowers reddish-purple, rarely white or yellowish; in summer.

(Latin name of the Safflower, from the Greek ??????.)

[*] _Scales of the involucre all tipped with spreading p.r.i.c.kles._

C. LANCEOLaTUS, Hoffm. (COMMON THISTLE.) Leaves decurrent on the stem, forming p.r.i.c.kly lobed wings, pinnatifid, rough and bristly above, woolly with deciduous webby hairs beneath, p.r.i.c.kly; flowers purple. (Cirsium, _Scop._)--Pastures and roadsides, everywhere, at the North. (Nat. from Eu.)

[*][*] _Heads leafy-bracteate at base_ (see also n. 8); _proper scales not p.r.i.c.kly._

1. C. horridulus, Pursh. (YELLOW THISTLE.) Stem stout (1--3 high), webby-haired when young; leaves partly clasping, green, soon smooth, lanceolate, pinnatifid, the short toothed and cut lobes very spiny with yellowish p.r.i.c.kles; heads (1--1' broad) surrounded by leaf-like and very p.r.i.c.kly bracts, which usually equal the narrow scales; flowers pale yellow or purple. (Cirsium, _Michx._)--Sandy fields, Ma.s.s. to Va., and southward, near the coast.

[*][*][*] _Scales appressed, the inner not at all p.r.i.c.kly._

[+] _Leaves white-woolly beneath, and sometimes also above; outer scales successively shorter, and tipped with short p.r.i.c.kles._

2. C. Pitcheri, Torr. _White-woolly throughout_, low; stem very leafy; _leaves all pinnately parted into rigid narrowly linear and elongated, sometimes again pinnatifid divisions_, with revolute margins; flowers cream-color. (Cirsium, _Torr. & Gray_.)--Sandy sh.o.r.es of Lakes Michigan, Huron, and Superior.

3. C. undulatus, Gray. _White-woolly throughout_, low and stout, leafy; _leaves lanceolate-oblong_, partly clasping, undivided, _undulate-pinnatifid_, or rarely pinnately parted, moderately p.r.i.c.kly; flowers reddish-purple. (Cirsium, _Spreng._)--Islands of L. Huron to Minn., Kan., and westward. The heads vary much in size.

4. C. altissimus, Willd. Stem downy, branching (3--10 high), _leafy quite to the heads; leaves_ roughish-hairy above, whitened with close wool beneath, _oblong-ovate to narrowly lanceolate, undivided, sinuate-toothed, undulate-pinnatifid, or twice pinnatifid_, the lobes or teeth weakly p.r.i.c.kly; heads 1--2' high; flowers chiefly purple.

(Cirsium, _Spreng._)--Fields and copses, Ma.s.s. to Minn., and southward.

Var. discolor, Gray. Stem 2--6 high; leaves nearly all deeply pinnatifid into lanceolate or linear lobes. (Cirsium discolor, _Spreng._)--Common; N. Eng. to Ill., and southward.

5. C. Virginia.n.u.s, Pursh. Stem woolly, slender, simple or sparingly branched (1--3 high), the _branches or long peduncles naked; leaves lanceolate_, green above, whitened with close wool beneath, ciliate with p.r.i.c.kly bristles, _entire or sparingly sinuate-lobed_, sometimes the lower deeply sinuate-pinnatifid; heads small; outer scales scarcely p.r.i.c.kly; flowers purple. (Cirsium, _Michx._)--Woods and plains, Va., Ohio, and southward.

[+][+] _Leaves green both sides, or only with loose cobwebby hairs underneath; heads large; scales scarcely p.r.i.c.kly-pointed._

6. C. muticus, Pursh. (SWAMP THISTLE.) _Stem tall_ (3--8 high), angled, smoothish, panicled at the summit; branches sparingly leafy, bearing single or few rather large _heads; leaves_ somewhat hairy above, whitened _with loose webby hairs beneath_ when young, _deeply pinnatifid, the divisions lanceolate_, acute, cut-lobed, p.r.i.c.kly-pointed; _scales of the webby and glutinous_ (sometimes glabrate) _involucre_ closely appressed, _pointless_ or barely mucronate; flowers purple. (Cirsium, _Michx._)--Swamps and low woods; common.

7. C. pumilus, Torr. (PASTURE THISTLE.) _Stem low_ and stout (1--2 high), hairy, bearing 1--3 very large _heads_ (1' broad), which are often _leafy-bracted_ at the base; _leaves green_, lanceolate-oblong, partly clasping, _somewhat hairy, pinnatifid, with short and cut very p.r.i.c.kly-margined lobes; outer scales p.r.i.c.kly-pointed_, the inner very slender; flowers purple or rarely white (fragrant, 2' long). (Cirsium, _Spreng._)--Dry fields, Maine to Penn., near the coast.

[*][*][*][*] _Outer scales of the appressed involucre barely p.r.i.c.kly-pointed; heads imperfectly dicious, small and numerous._

C. ARVeNSIS, Hoffm. (CANADA THISTLE.) Perennial, slender, 1--2 high, the roots extensively creeping; leaves oblong or lanceolate, smooth, or slightly woolly beneath, sinuate-pinnatifid, p.r.i.c.kly-margined; flowers rose-purple. (Cirsium, _Scop._)--Cultivated fields, pastures, and roadsides, common; a most troublesome weed, extremely difficult to eradicate. (Nat. from Eu.)

80. CaRDUUS, Tourn. PLUMELESS THISTLE.

Bristles of the pappus naked (not plumose), merely rough or denticulate.

Otherwise as in Cnicus. (The ancient Latin name.)

C. NuTANS, L. (MUSK THISTLE.) Biennial; leaves decurrent, sinuate, spiny; heads solitary, drooping; flowers purple.--Fields near Harrisburg, Pa., _Prof. Porter_. (Adv. from Eu.)

81. ONOPoRDON, Vaill. COTTON or SCOTCH THISTLE.

Receptacle deeply honeycombed, not setose. Pappus not plumose. Otherwise as Cnicus.--Coa.r.s.e, branching annuals, or biennials, with the stems winged by the decurrent base of the lobed and toothed somewhat p.r.i.c.kly leaves. Heads large; flowers purple. (The ancient Greek name of the plant.)

O. ACaNTHIUM, L. Stem (2--4 high) and leaves cotton-woolly; scales linear-awl-shaped.--Roadsides and waste places in the Atlantic States; rather rare. July--Sept. (Adv. from Eu.)

82. CENTAUReA, L. STAR-THISTLE.

Heads many-flowered; flowers all tubular, the marginal often much larger (as it were radiate) and sterile. Receptacle bristly. Involucre ovoid or globose, imbricated, the scales margined or appendaged. Achenes obovoid or oblong, attached obliquely at or near the base; pappus setose or partly chaffy or none.--Herbs with alternate leaves and single heads.

(Named from the _Centaur_, Chiron, famous for his skill in healing.)

[*] _Achenes terete, 10-dentate; pappus of 10 long bristles and 10 short inner ones._

C. BENEDiCTA, L. Low branching annual, with clasping scarcely pinnatifid cut leaves, and large sessile leafy-bracted heads; flowers yellow.

(Cnicus benedictus, _L._)--Roadsides and waste grounds, S. Atlantic States; rare. (Adv. from Eu.)

[*][*] _Achenes compressed or 4-angled; pappus very short or none._

C. C?a.n.u.s, L. (BLUEBOTTLE.) Scales of the globular involucre fringe-margined; _false rays large_; pappus very short; _leaves linear, entire_, or toothed at the base; root annual.--Roadsides, escaped from gardens. July.--Flowers blue, varying to purplish or white. (Adv. from Eu.)

C. NGRA, L. (KNAPWEED.) Scales of the globular involucre appendaged, and with a black pectinately ciliate fringe; _rays wanting_; pappus very short; _leaves lanceolate_, entire, or the lower lyrate-toothed, rough; root perennial.--Waste places, E. New Eng. Aug.--Flowers purple. (Adv.

from Eu.)

C. CALCiTRAPA, L. (STAR-THISTLE.) Stem diffusely much branched; _leaves pinnately lobed_ or spinulose-toothed; heads sessile, the middle _scales of the ovoid involucre spiny_; pappus none; flowers purple; root annual.--Seaports, N. Y., and southward. (Adv. from Eu.)

C. JaCEA, L. Like the last; heads rather larger, the brownish scale-appendages lacerate; rays conspicuous, palmate.--Charlotte, Vt.

(_Pringle_); near N. Y., etc., on ballast. (Nat. from Eu.)