18 Flora of Denver. 



137. Opuntia Missouriensis DC. (COMMON CACTUS.) The 

 common flat-jointed cactus with numerous clusters of spines. 

 Flowers yellow, rarely red near Denver. Fruit dry. Common 

 on the plains, blooming in early summer. 



UMBELLIFER^E. (Parsley Family.) 



138. Heracleum lanatum MICHX! (Cow-PARSNiP.) Tall 

 and stout, large ternately compound leaves with broad leaflets, 

 many rayed umbels of white flowers. Along the Platte and 

 Cherry Creek. Summer. 



139. Peucedanum nudicaule NUTT. On the hills at Berk- 

 eley in spring. 



140. Cymopterus glomeratus RAF. The earliest bloomer 

 on the plains. Low with white flowers and shiny compound 

 leaves. Carpels winged. 



141. Cymopterus montanus TORR. & GRAY. Similar to 

 preceding, flowers pinkish and leaves glaucous. In North Den- 

 ver. It is likely to be found where the soil is adobe. Early 

 spring. 



142. Musenium trachyspermum NUTT. Low branching 

 from near the root, flowers yellow, fruit rough. North Denver 

 and Valverde hills. Spring. 



143. Cicuta virosa L. var. maculata COULTER & ROSE. 

 (POISON-HEMLOCK.) Stout and tall, leaves twice or thrice pin- 

 nate with lanceolate-acuminate serrate leaflets. A flat-topped 

 umbel of white flowers. This grows in the water and is found 

 along Cherry Creek and the Platte. Summer. 



144. Berula angustifolia KOCH. A slender, branching 

 marsh plant with pinnately compound leaves, leaflets from 

 toothed to incised. Flowers white, involucre and involucels 

 present. 



145 Pastinaca sativa L. The common parsnip. Introduced. 



