COMPOSITJE. (composite FAMILY.) 265 



78. ARTEMISIA, L. Wormwood. 



Heads few- or many-flowered, discoid ; the central flowers perfect, 5-toothed 

 (sometimes abortive), tlie marginal ones pistillate, Stoothed. Scales of the 

 involucre imbricated, mostly with scarious margins. Receptacle convex, 

 naked or villous. Achenia obovoid. Pappus none. — Aromatic herbs or 

 shrubs. Leaves alternate, pinnately divided. Heads small, in panicled spikes 

 or racemes. 



1. A. caudata, Michx. Smooth; stem slender, branching; lowest 

 leaves 2 - 3-pinnately divided, the upper ones pinnate, with the divisions fili- 

 form ; heads globular, in small racemes, forming an elongated panicle. — Dry 

 opeu woods. West Florida, and northward. Sept. (2) — Stem 2° -6° high. 

 Receptacle naked. Disk flowers abortive. 



2. A. vulgaris, L. (Mugwort.) Stem branching ; leaves white-downy 

 beneatli, pinuatifid, with the lobes lanceolate ; heads downy, iu slender ter- 

 minal spicate panicles ; flowers all perfect. — Waste grounds. Introduced. 



3. A. biennis, Willd. Biennial, smooth; stem simple (l°-3° high); 

 leaves 1 - 2-pinnatifid, the linear lobes sharply toothed ; heads crowded in 

 terminal and axillary spikes, wliich form a long narrow leafy panicle ; flowers 

 all perfect. — West Tennessee. 



4. A. annua, L. Annual, glabrous; stem 2° -3° high, pauiculately 

 branched; leaves bipinnately divided, the lobes incised; panicles spreading ; 

 heads nodding. — Tennessee. Introduced. 



79. SOLIVA, Ruiz & Pavon. 



Heads many-flowered, mona'cious ; the fertile flowers in several rows, apeta- 

 lous or nearly so ; the staminate few in the centre, with a 3 - 6-tootlied corolla. 

 Scales of the involucre 5 - 10, in a single row. Receptacle flat, naked. Ache- 

 nia compressed, with winged or thickened margins, armed with the persistent 

 rigid style. Pappus none. — Small depressed herbs, with petiuled pinnately 

 divided leaves, and small sessile or rarely pedunculate heads. 



1. S. nasturtiifolia, DC. Very low and depressed; leaves on short 

 petioles, pinnately parted ; the lobes 3 - 4 on each side, obtuse, entire ; heads 

 sessile ; achenia cuneiform, villous at the apex ; the callous margin tubercu- 

 late-rugose throughout. — South Carolina, around Charleston. Introduced. 

 Feb. - May. 



80. ARNICA, L. 



Heads many-flowered, radiate ; the rays pistillate. Scales of the campanu- 

 late involucre lanceolate, equal, in about two rows. Receptacle flat, hairy. 

 Achenia terete, narrowed downward, somewhat ribbed. Pappus a single 

 row of rough bristly hairs. — Perennial herbs. Leaves opposite, undivided. 

 Heads single or coryml)ose. 



1. A. nudioaulis, Xutt. Hirsute; radical leaves spreading, oval or 

 obovate, obtuse, 3 -5-ril)bed, serrate or entire; tiie others (2-3 pairs) dis- 

 tant, oblong, sessile ; heads corymbose, showy ; achenia smoothisli. — Wet 

 pine barrens, Florida, and northward. April -May. — Stem l°-2^ Jiigh, 

 simple, or with few opposite branches. 



