-30 Flora of Denver. 



237. Lactuca Canadensis L. Usually tall, sometimes nine 

 feet; leaves hairy on the mid vein, runcinate pinnatifid; heads 

 small, crowded in a diffuse panicle, rays yellow. Along the 

 Platte. Summer. 



238. Lactuca Ludoviciana DC. Stem erect, simple to the 

 diffusely branching almost leafless panicle; leaves veiny, au- 

 riculate clasping, spiny on the midrib and spiny-toothed on 

 the margins; heads of small yellow flowers numerous ex- 

 panded for a short time in the morning. They seem like 

 little stars all along the stem. Common in waste grounds. I 

 believe that it is introduced around Denver. 



239. Lactuca pulchella DC. Bright blue flowers con- 

 spicuous in the morning; rays nearly half an inch long. It 

 looks like an aster, but the flowers all have rays, and the juice 

 is milky. Common along streams. Summer. 



240. Sonchus oleraceus L. (Sow-TniSTLE.) Introduced 

 sparingly. 



241. Sonchus asper VILL. (SPINY-LEAVED SOW-THISTLE.) 

 Sparingly introduced. 



LOBELIACE^E. 



242. Lobelia syphilitica L. Simple-stemmed, flowers 

 blue, sometimes fose colored or white, in racemes, found in 

 swampy places in the fall. It might be mistaken for a Pen- 

 stemon, but can readily be distinguished by the milky juice 

 and the corolla open to the base on one side. 



CAMPANULACE^E. 



243. Specularia perfoliata A. DC. I found a plant years 

 ago along the Platte near the C. C. Bridge. I have not seen 

 it since. 



