Genus S9.] 



THISTLE FAMILY. 



469 



89. TUSSILAGO h. Sp. PI. 865. 1753. 



An acaulescent herb, more or less white-tomentose, with slender perennial rootstocks, 

 broad basal cordate, dentate or lobed, long-petioled leaves, and large solitary, monoecious 

 heads of both tubular and radiate yellow flowers at the summit of a scaly scape, appearing 

 before the leaves of the season. Involucre campanulate to cylindric, its principal bracts in 

 a single series, equal, with or without a few shorter outer ones. Receptacle flat, naked. Ray- 

 flowers in several series, pistillate, fertile. Disk-flowers perfect, sterile, the corolla 5-cleft, 

 the style undivided and obtuse, lobed. Achenes of the ray-flowers linear, 5-10-ribbed. Pap- 

 pus copious, of numerous slender roughish bris- 

 tles, that of the sterile flowers shorter than that 

 of the fertile. [Latin, tussis, cough, for which 

 the plant was a reputed remedy.] 



A monotypic genus of northern Europe and Asia. 



i. Tussilago Farfara L. Coltsfoot. 

 Coughwort. (Fig. 4019.) 



Tussilago Farfara L. Sp. PI. 865. 1753. 



Scape slender, 3 / -i8 / high, bearing a solitary 

 large head at the summit. Leaves nearly orbicu- 

 lar, or broadly ovate-reniform, angulately lobed 

 and dentate, 3 '-7' broad, green and glabrous 

 above, persistently white-tomentose beneath; 

 head about i' broad; involucre campanulate; 

 rays bright yellow, numerous, linear, pistillate, 

 fertile. 



In moist soil, along roadsides, etc., Nova Scotia 

 and New Brunswick to Massachusetts, New York 

 and Minnesota. Naturalized from Europe. Other 

 names are Horse-foot, Horse-hoof, Dove-dock, Sow- 

 foot, Colt-herb, Hoofs, Cleats, Ass's-foot, Bull's- 

 foot, Foal-foot, Ginger, Clay-weed. April-June. 



90. PETASITES Gaertn. Fr. & Sem. 2: 406. pi. 166. 



Herbs with perennial thick horizontal rootstocks, broad basal petioled leaves, and scaly 

 scapes bearing racemose or corymbose heads of tubular or both tubular and radiate, white or 

 purplish, often dioecious or subdioecious flowers. Involucre campanulate to cylindric, its 

 bracts in 1 series, equal. Receptacle flat, or nearly so, not chaffy. Corolla of pistillate flow- 

 ers very slender, 2-5-toothed, truncate or sometimes with a ray, marginal, or composing most 

 of the head; perfect but sterile flowers with a tubular 5-cleft corolla, the style undivided. 

 Anthers entire or minutely sagittate at the base. Fertile achenes linear, the pappus of nu- 

 merous capillary rough or barbellate bristles. [Greek, a broad-rimmed hat, referring to the 

 broad leaves of these plants.] 



About 12 species, natives of the north temperate and subarctic zones. 

 Flowers whitish, the pistillate radiate; natives; northern. 



Leaves orbicular, 7-11-cleft nearly to the base. I. P- palmata. 



Leaves hastate-reniform, sinuate-lobed or toothed. 2. P. frigida. 



Leaves deltoid-ovate, repand-denticulate. 3- P- sagittaia. 



Flowers all rayless, purple; introduced. 



4. P. Petasites. 



i. Petasites palmata (Ait.) A. Gray. 

 Palmate-leaf Sweet Coltsfoot. (Fig. 4020.) 



Tussilago palmata Ait. Hort. Kew. 2: iSS. pi. 2. 1789. 

 Nardosmia palmata Hook. Fl. Bor. Am. 1:308. 1S33. 

 Petasites palmata A. Gray in Brew. & Wats. Bot. Cal. 



1:407. 1S76. 



Scape very scaly, stout, 6 / -24 / high. Leaves 

 nearly orbicular in outline, 3 / -i2 / broad, deeply 

 7-11-cleft to much beyond the middle, green and 

 glabrous above, densely white-tomentose beneath, 

 at least when young, sometimes becoming glabrate, 

 the lobes oblong or obovate, acute, often somewhat 

 cuneate, sharply dentate or incised; heads mostly 

 dioecious, corymbose or racemose-corymbose, nu- 

 merous, 4 // -6 // broad; flowers nearly white,fragrant, 

 the marginal ones of the pistillate heads radiate. 



In swamps and along streams, Newfoundland to 

 Alaska and British Columbia, south to Massachusetts, 

 New York, Wisconsin and California April-June. 



