COMPOSITE 409 



sessile, simple, lanceolate, acuminate, serrate, the bases sometimes united: 

 outer involueral bracts exceeding the inner, but shorter than the yellow, 

 oval or oblong raj-s: raj's about 1 in. long, 8 or 10 in number: akenes small, 

 wedge-shaped, truncate, prickly on margins, with 2 rigid downwardly 

 barbed awns. 



B. bipinntlta, Linn. Annual: stem quadrangular, erect, branching 

 freely: leaves 1 to 3 times pinnate, leaflets lanceolate, pinnatified: heads 

 small on slender peduncles: rays short, pale yellow, 3, 4 or more: akenes 

 smooth, 3-4 grooved, 2- or 6-awned (awns barbed). 



21. COREOPSIS. TicKSEED. 



Low herbs with opposite, sometimes alternate leaves: heads of tubular 

 and ray flowers solitary, or corymbed on long peduncles: involucre double, 

 bracts all united at base, the 8 outer ones usually leafy: the inner erect: 

 receptacle chaffy: ray flowers neutral, usually yellow: disk flowers tubular, 

 perfect, yellow or purple: pappus of 2 short teeth or a crown-like border, or 

 none: akenes flat, often winged, 2-toothed or 2-armed. A number of rather 

 showy but somewhat weedy plants. 



C. tinctdria, Nutt. Calliopsis. Annual or biennial, glabrous, erect, 1-3 

 ft.: disk flowers dark purple: ray flowers about 8, yellow with purple bases, 

 the edges coarsely 3-toothed: leaves alternate, 2 or 3 times pinnately- 

 divided: the lower petioled, the upper sessile and often entire: heads 1-1 K 

 in. wide, on slender peduncles. A favorite in gardens. Ray flowers variable 

 in shape and coloring. 



C. tripteris, Linn. Tall and leafy stems, 4-9 ft.: disk and ray flowers 

 all yellow: heads small, numerous, l-lj^ in. broad, corymbed, giving a spicy 

 odor when bruised. Perennial. Weed, common. 



C. lanceolita, Linn. Perennial, native and cultivated: nearly or quite 

 glabrous: leaves oblong or linear, mostly entire, obtuse: heads large, yellow 

 rayed, on very long stems. 



22. CNlCUS. Thistle. 



Perennial or biennial herbs, with pinnatified, very prickly leaves: florets 

 all tubular and usually all perfect: scales of the involucre prickly: torus 

 bristly: pappus of soft bristles, by means of which the fruit is carried in the 

 wind. Several species in our territory. 



C. lanceol^tus, Ilollm. Common thistle. Figs. 228-230, 276. Stror.g, 

 branching biennial : leaves pinnatifid, decurrent, woolly beneath : neads 

 large, purple, with all the involucre-scales prickly. Europe. 



C. arv6nsi8, Hoffm. Canada thistle. Lower, perennial and a pestiferous 

 weed: leaves smooth or nearly so beneath: flowers rose purple, in small, 

 imperfectly dioecious heads, only the outer scales prickly. Europe. 

 "3. ABCTIUH. Burdock. 



Coarse biennials or perennials, strong-scented, with large dock-liko 

 ■imple leaves: head becoming a bur with hooked bristles, the florets all 

 tubular and perfect: torus bristly: pappus of short, rough, deciduous bristles. 



