composite:. 203 zinnia. 



20. A'RNICA. 



Involucre of equal, lanceolate scales, 1 or 2 rowed ; ray- 

 flowers pistillate, disk perfect; receptacle flat, with scattered 

 hairs; pappus simple, rigid and serrulate. 



Said to be a corruption of the Lat. ptarmica, sneezing; one of the species 

 is a violent sternutatory. Perennial herbs. Stems simple. Lvs. opposite. 

 Fls. yellow. 



A. MOLLIS. Hook. 



Stem pubescent, erect ; leaves pubescent, becoming nearly glabrous, thin, 

 veiny, dentate, ovate-lanceolate and oblong; radical ones stalked ; cauline, 

 sessile ; heads few ; involucre hairy with acuminate scales ; aclienia hairy. 

 An alpine plant found in ravines on the White Mts., and also, according to 

 Drs. Torrey <^ Gray, on the Mts. in Essex Co., N. Y. Stem 1 — 2 feet high, 

 with several pairs of sessile leaves, and 1 — 5 yellow heads of middle size. 

 Leaves 2 — 5 inches in length, the upper ones broad at the base, the lower 

 tapering to a winged petiole, often acute but not acuminate. 



21. POLY'MNIA. 

 Involucre double, outer of 4 or 5 large, leafy scales, inner 

 of 10 leaflets, concave ; ray-flowers pistillate, few; disk sterile ; 

 receptacle chaffy ; pappus none. 



Polymnia is the name of one of the ancient Muses ; why applied to this 

 plant is not obvious. Perennial, clammy herbs. Lvs. opposite. Fls. yellow. 



1. P. Canade'nsis. 



Viscid-villous ; leaves denticulate, petiolate, acuminate, lower pinnatifid, 

 upper 3-lobed or entire. A coarse, broad-leaved, hairy-viscid plant, 3--5 

 feet high, at Niagara Falls and elsewhere. Stem with opposite leaves and 

 spreading branches. Flowers light-yellow, the rays short, surrounded by the 

 concave leaflets of the double calyx in such a manner as to form a sort of cup, 

 hence called leaf-cup. Leaves feather-veined, 3 — 8 inches long, and nearly 

 as wide, lobes deeply divided and acuminate. Heads half an inch in diame- 

 ter. June. Canadian Folynmia. 



'2. P. uveda'lia. 



Leaves opposite, 3-lobed, acute, decurrent into the petiole, lobes sinuate- 

 angled ; ra?/s elongated. In highland woods. Stem 3 — 6 feet high. Lower 

 leaves very large. Flowers large, yellow, the rays much longer than the 

 involucre. July. Yellow Leaf-cup. 



2 2. Z I' N N 1 A . 



Involucre scales oval, margined, imbricate; rays 5, persis- 

 tent, entire, pistillate; disk flowers perfect ; i-eceptacle chatfy, 

 conical; pappus of the disk of 2 erect awns. 



Named for John Godfrey Zinn, a German botanist, 1557. Annual herbs, 

 native at the South, «St,c. Lvs. opposite, entire. 



1. Z. E LEGANS. — Heads pedunculate; leaves cordate, ovate, sessile- 

 amplexicaul; stem ha.iiy, c/io/^ serrated. Native of Peru. July, Aug. 



Purplc-Jlowered Zinnia, 



