442 



COMPOSITAE. 



VOL. III. 



36. LEPTILON Raf. Am. Month. Mag. 2 : 268. 1818. 

 [CAENOTUS Raf. Fl. Tell. 2 : 50. 1836.] 



Annual or biennial herbs, with small racemose thyrsoid or panicled heads of white 

 flowers, the rays small, usually shorter than the diameter of the disk, or none. Involucre 

 mostly campanulate, its narrow bracts in 2 or 3 series. Receptacle naked. Ray-flowers 

 pistillate ; disk-flowers perfect, their corollas usually 4-lobed or 4-toothed, the anthers obtuse 

 at the base; style-branches somewhat flattened, their appendages short. Achenes flattened. 

 Pappus of numerous simple fragile bristles in i series. [Greek, referring to the small heads.] 



About 20 species, natives of America and Asia. Besides the following, 2 or 3 others occur in 

 the southwestern United States and one is naturalized from Asia on the southern Atlantic and 

 Pacific coast. Type species: Leptilon divaricatum (Michx.) Raf. 



i. Leptilon canadense (L.) Britton. Horse- weed. Canada Fleabane. 



Fig- 4378. 



Erigeron canadensis L. Sp. PI. 863. 1753. 



Leptilon canadense Britton, in Britt. & Brown, 111. 

 Fl. 3: 391- 1898. 



Stem hispid-pubescent or glabrate, 3'-io high, 

 the larger plants paniculately much branched. 

 Leaves usually pubescent or ciliate, the basal and 

 lower spatulate, petioled, incised, dentate or en- 

 tire, i '-4' lon'g, obtuse or acutish, those of the 

 stem linear and mainly entire; heads usually very 

 numerous ; about 2" broad ; involucre campanu- 

 late, i"-ii" high, its bracts linear, acute, gla- 

 brate, the outer shorter; rays numerous, white, 

 shorter than the pappus and mostly shorter than 

 their tubes. 



In fields and waste places, a common weed through- 

 out North America except the extreme north. Widely 

 distributed as a weed in the Old World, the West 

 Indies and South America. Butter-weed. Prideweed. 

 Fireweed. Blood-staunch. Cow's-, mare's- or colt's- 

 tail. Hogweed. Bitter-weed. June-Nov. 



2. Leptilon divaricatum (Michx.) Raf. Low 



Horse-weed. Purple Horse-weed. Dwarf 



Fleabane. Fig. 4379. 



Erigeron divaricatus Michx. Fl. Bor. Am. 2: 123. 1803. 

 Leptilon divaricatum Raf. Am. Month. Mag. 2: 268. 1818. 



Stem diffusely much branched, 3'-i2' high, pubescent 

 or hirsute. Leaves all linear or subulate, entire, 4"-i2" 

 long, about \" wide, the uppermost minute; heads nu- 

 merous, about 2" broad ; involucre campanulate, i" 

 high, its bracts linear, acute, pubescent, the outer 

 shorter; rays purplish, shorter than their tubes. 



In sandy soil, especially along rivers, Indiana to Minne- 

 sota, Tennessee, Louisiana, Nebraska and Texas. June-Oct, 



