* Scales of the involucre with a fringed or pectinate appendage.....
* Scales of the involucre merely ciliate, or tipped with a spine.........
.Nos. 3, 4
1 C. nigra L. St. erect, branched, pubescent above; lower lvs. angular-lyrate, upper lanceolate, dentate, scales ovate, with an erect, capillary, fringed appendage; ray and disk-fls. alike. - Ц A troublesome weed, in meadows and pastures, Mass. St. about 2f high, simple, or oftener divided into elongated branches. Hds. few, large, terminal, solitary. Fringed appendage of the scales dark brown. Fls. purple. Jl., Aug. § Eur.
2 C. Americana Nutt St erect, sulcate, sparingly branched; lower lvs. oblong-ovate, repand-dentate, upper ones lanceolate, acute, all sessile and glabrous; hds. few or solitary, very large; ped. thickened at summit; ray fls. twice longer than the disk; scales with a pectinate-pinnate, reflexed appendage. - (1) Ark. and La., naturalized in I11. (Mead.) Cultivated in gardens. St. 2 to 4f high, with large, showy, pale-purple hds. Appendages straw-color, †
3 C. Cyanus L. Bachelor's-button. St. erect, branching, downy ; lvs. linear, entire, downy, the lowest subdentate; scales ciliate-serrate ; ray flowers much enlarged. - (1) Cultivated and sparingly naturalized in old fields. It is a hardy annual, justly popular for its handsome flowers which are very variable in color. Hds. ovoid, solitary on the ends of the branches. Jl. - Sept. § Eur.
4 C. Calcitrapa L. Star Thistle. St. diffusely branched, hairy; lvs. sessile, pinnately lobed, lobes linear, toothed, upper mostly entire; hds. sessile ; middle scales tipped vrith a strong, spreading spine with 1 or 2 minute spines each side; pappus 0. - (1)(2)Va. Fls. purple. § Eur.
92. AMBER'BOA, DC. Sweet Sultan. Heads discoid ; involucre imbricated ; ray-flowers wanting or larger than the rest, sterile ; pappus of oblong or obovate pales, attenuated to the base, all similar, rarely small or 0. - Eastern herbs with alternate lvs.
1 A. moschata Willd. Lvs. lyrate-dentate; in vol. subglobous, smooth; scales ovate; ray-flowers scarcely enlarged, not exceeding the disk; pappus 0.- A handsome border annual from Persia. Flowers purple. A variety has white flowers. July - Oct. (Centaurea L.) †
2 A. odorata, a. amboracea. DC. Yellow Sweet Sultan. Lower lvs. broadly subspatulate, dentate, upper lyrate at base; hds. globous; ray-fls. enlarged upwards, longer than the disk; pappus chaffy, a little shorter than the fruit. - From Levant. Leaves scarcely pinnatifid. Flowers yellow, † (Centaurea suaveolen3 Willd.)
▀GLAUCA. Lvs. often deeply pinnatifid; flowers purple. † (Centaurea glauca Willd.)
93. CAR'THAMUS, L. Saffron. (Arabic, qorthom, to paint; from its coloring property.) Heads discoid; involucre imbricated, outer bracts foliaceous ; flowers all tubular and , filaments smooth ; pappus 0; receptacle with setaceous pales; achenia 4-angled. - Oriental herbs.
C. tinctorius L. St. smooth; lvs. ovate-lanceolate, sessile, spinous-denticulate. - (1) Native of Egypt, but long cultivated in other lands on account of itsorange-colored flowers. Stem branching, striate, 1 - 2f high. Leaves subamplexicaul, smooth and shining. Heads large, terminal, with numerous long and slender flowers. The latter are useful in coloring, and as a nursery medicine.
94. CNICUS, Vaill. Blessed Thistle. (Gr, , to prick ; well applied to these herbs) Heads discoid; involucre ventricous, imbricate with doubly spinous scales ; ray-flowers sterile ; receptacle very hairy; pappus in 3 series, the outer 10-toothed, the 2 inner each 10-bristled. - Oriental herbs.
C benedictus L. Lvs. somewhat decurrent; dentate and spiny; invol. doubly spinous, woolly, bracteate. - (1) Native of Persia, Tauria and Greece. About 2f high, with yellow flowers. Sparingly naturalized. June. - It was formerly in great estimation in medicine, but is now considered worthless.
95. ONOPOR'DON, Vaill, Cotton Thistle. Heads discoid, homo-gamous ; involucre ventricous, imbricate with spreading, spinous scales; receptacle deeply alveolate ; pappus copious, capillary, scabrous; achc-nia 4-angled. - Large, branching herbs, with decurrent leaves.
O. acanthium L. Invol. scales spreading, subulate; lvs. ovate-oblong, decurrent, sinuate, spinous, woolly on both sides. - (2) This fine looking thistle occurs naturalized in waste grounds, and is about 3f in height. The whole plant has a white, cottony appearance. Stem winded by the decurrent leaves, which are unusually large. Involucre round, cottony, spinous. Flowers purple. July, Aug. § Eur.
96. CIR SIUM, Tourn. (Cuicus L. Muhl.) Thistle. (Gr. a swelling of a vein, which this plant was supposed to heal.) Heads discoid, homogamous; involucre subglobous, of many rows of spi-nous-pointed, imbricated scales; receptacle bristly; style scarcely divided; pappus copious, plumous; achenia compressed, smooth.- Herbs with alternate lvs., generally armed with spinous prickles. Fls. cyanic.
* Leaves decurrent on the stem more or less. Scales tipped with spines....
Nos. 1, 2
* Leaves not decurrent. - Heads involucrate with a whorl of 12 to 20 spiny bracts.....
-Heads naked. - Flowers ochroleucous. Scales prickly.......
- Fls. purple. - Lvs. white-tomentous beneath..
Nos. 5 - 7
- Lvs. green. - Stem low, simple..
Nos. 8, 0
-Stem tall, branched
"10 - 12
1 C. lanceolatum Scop. Common Thistle. Lvs. decurrent, pinnatifid, hispid, the segments divaricate and spinous; hds. several, ovoid, villous; scales lanceolate, tipped with a spine, spreading. - (2) Common in borders of fields, roadsides, N. Eng. and Mid. States, always distinguished by the decurrent leaves. St. 3 to 4f high, winged by the decurrent leaves which are white and woolly beneath, armed with formidable spines at all points. Fls. numerous, large, purple. Invol. scales, webbed, each ending in a spine. Jl. - Sept.
2 C. Lecontii Torr. & Gr. Slender, simple, with one head; lvs. linear-lanceolate, more or less decurrent, with a few spinous teeth, glabrous above, white-floccous beneath, invol. ovoid, arachnoid when young; scales not spinous, merely mucro nate or acuminate-pointed. - Ga. to La, St. about 2f high. Hd. large, (1' or more diam.) terminal.