170 COMPOSITE. 



Woods and low places; rare. Aug.. Sept. Stem simple, about 2 feet high, often 

 several from the same root. Leaves smooth, pale giecn. 1 to 2 inches long, % to "% 

 inch wide. Heads in a flat-topped corymb. Hays white, longer than the drek. 

 Pappus white. 



2. S. conyzoides, Nees. Broad-leaved Sericocarpus. 



Slightly pubescent; leaves oblong-lanceolate or the lower spatulate, obscurely 

 3- nerved, smooth beneath, acute at each end, ciliate; lower serrate towards the 

 apex ; involucre top-shaped ; heads rather loosely corymbed ; rays short. 



Dry woods; common. July — Sept. Stem 1 to 2 feet high, somewhat 5-angled, 

 rigid, but rather slender. Le aves somewhat fleshy. Heads few in small clusters 

 fiays longor than the disk, white. 



15. CALLISTEPHUS, Cans. 



Gr. hallos, beautiful, and stcphos, a crown. 



Ray-flowers pistillate, numerous; disk-flowers perfect. 

 Involucre hemispherical. Receptacle sub-convex. Pap- 

 pus double, each in one series, outer series short, chaffy, 

 bristly, with the bristles united into a crown ; inner series of 

 long, thread-like, rough, deciduous bristles. — Exotic annuals 

 with alternate leaves and showy heads of flowers. 



1. C. Chinensis, Nees. China Aster. Queen Margaret. 



Stem hisped; branches divergent, 1-fiowered; leaves orate, coarsely dentate, petio- 

 late ; stem leaves sessile, wedge-shaped at the base. — Native of China. Cultivation 

 has produced many beautiful varieties, double and semi-double, with white, blue, 

 red, flaked and mettled rays. Stem 15 to 20 inches high, with long branches, each 

 terminated by a single large head. Disk yellow. July — Sept. 



16. DAHLIA, Linn. 



In honor of Andrew Dahl, a Swedish botanist. 



Involucre double, the outer series of many distinct 

 scales, the inner of 8 scales united at base. Receptacle 

 chaffy. Pappus none. — Showy Mexican perennial plants, 

 with opposite pinnate leaves, and showy large heads of flowers. 



1. D. variabilis, Desf. (D. superflua. Ait.) 



Stem green : racJies of the leaves winged ; leaflets ovate, acuminate, serrate, pubcr- 

 ulont or nearly smooth; outer involucre reflexed; ray-flowers pistillate, sterile or 

 fertile. — Stem 2 to 4 feet high. Leaves coarse and roughhh resembling those of the 

 common elder. Flowers large and beautiful, sporting into innumerable varieties, 

 single and double, of every conceivable shade of white, scarlet, crimson, purple, 

 red, rarely yellow, blooming from Aug. until arrested by frost. 



2. D. COCCINEA, Cav. (D.flrustranea. Ait.) 



Stem frosty, or hoary, hollow; leaves with the rachis naked ; leaflets roughish be « 

 neath ; outer involucre spreading ; rays neutral.— Stem 3 to 4 feet high. Leavit 

 .glaucous. Bays scarlet, orange-colored or yellow, never purple ox white. 



Section 2. Heads radiute ; rays vcllov;. 



