47 



COMPOSITAE. 



[Vol.. III. 



2. Petasites frigida (L,.) Fries. 

 Arctic Sweet Coltsfoot. (Fig. 402 r.) 



Tussilago frigida L. Sp. PI. 865. 1753. 



Petasites frigida Fries. Summa Veg. Scand. 182. 



1845. 



Scape very scaly, 3 / -io / high. Leaves hastate- 

 reniform to triangular-ovate, \'-\ f long, irregu- 

 larly and angulately lobed and incised, green 

 and glabrous above, persistently white-tomen- 

 tose beneath, the lobes entire or few- toothed; 

 heads usually fewer and larger than those of the 

 preceding species; involucre short-campanulate; 

 flowers nearly white, fragrant, the margiual ones 

 of the pistillate heads radiate. 



Lake Winnipeg (according to Richardson), to the 

 Arctic Sea, west to Alaska and the mountains of 

 British Columbia. Also in northern Europe and 

 Asia. June-Aug. 



3. Petasites sagittata (Pursh) A. 



Gray. Arrow-leaf Sweet Coltsfoot. 



(Fig. 4022.) 



Tussilago sagittata Pursh, Fl. Am. Sept. 332. 1814. 

 Nardosmia sagittata Hook. Fl. Bor. Am. 1: 307. 



i833- 

 Petasites sagittata A. Gray in Brew. & Wats. Cal. 



Bot. 1: 407. 1876. 



Scape and racemose-corymbose inflorescence 

 similar to those of the two preceding species. 

 Leaves deltoid-ovate or reniform-ovate, persist- 

 ently white-tomentose beneath, glabrous or 

 nearly so above, 4 / -io / long, their margins sinu- 

 ate denticulate, neither cleft nor lobed; involucre 

 campanulate; flowers nearly white, the marginal 

 ones of the pistillate heads radiate. 



In wet ground, Hudson Bay to Manitoba and 

 Minnesota, west to British Columbia, south in the 

 Rocky Mountains to Colorado. May-June. 



4. Petasites Petasites (L,. ) Karst. 



Butter-bur. Butterfly-dock. 



(Fig. 4023.) 



Tussilago Petasites L. Sp. PI. 866. 1753. 

 Petasites officinalis Moench. Meth. 568. 1794. 

 Petasites vulgaris Desf . Fl. Atlant. 2: 270. 1798. 

 P. Petasites Karst. Deutsch. Fl. 1062. 1880-83. 



Scape very scaly, 6'-i5' high. Leaves or- 

 bicular or hastate-reniform, often 12' broad 

 when mature, rounded or pointed at the apex, 

 repand-denticulate all around, persistently 

 white-tomentose beneath, green and mostly 

 glabrous above; heads 4 // -6 // broad, mostly 

 dioecious, in a dense raceme, the staminate 

 ones smaller than the pistillate; flowers pink- 

 purple, fragrant, none of them radiate. 



In cultivated and waste ground, Bucks Co. to 

 Delaware Co., Pa. Naturalized from Europe. 

 Native also of northern Asia. Other names are 

 Batter-, Butter- or Flea-dock, Bog- or Poison- 

 rhubarb, Eldin, Gallon, Umbrella-leaves, Pesti- 

 lence-wort, Ox-wort. April. 



