The Shrubs of Wyoming. 19 



Ninebark ( Opulaster pauciflorus (T. & G.) Heller). 



With larger leaves and more showy flowers than the preced- 

 ing. It is a handsome shrub, often 4 to 5 feet tall, very desirable 

 for cultivation. It is known to occur in the Yellowstone Na- 

 tional Park and will perhaps be found in other parts of northern 

 Wyoming. % ... 



Nuttall's Spiraea (Spiraea densifolia Nutt.) 



Tufted and with erect branched stems, one to two feet high, 

 arising from underground rootstalks. It has oblong leaves, 

 one to one and a half inches long and the slender erect branches 

 are terminated by small but dense clusters of purple or rose- 

 colored flowers. A very handsome shrub of a low and some- 

 what bedded habit of growth, occurring in the mountains of 

 northwestern Wyoming. 



There is another closely related species (Spiraea lucida 

 Dougl.), having unbranched stems and larger clusters of white 

 flowers, which is found in the Teton mountains and in the 

 northern part of the state. 



Holodiscus dumosus (Nutt.) Heller. 



A diffuse shrub, often 4 feet high or more, with very large 

 clusters of small white flowers terminating the branches. It 

 has small broad leaves which are silky beneath but 

 green above, deeply toothed above the broadly 

 wedge-shaped base. 



There is apparently no common name for this 

 handsome and profusely flowered shrub. It is 

 found on rocky slopes and ledges at lower altitudes 

 in the state. In Central Wyoming it is especially common. It 

 is an exceedingly pretty bush when in flower, and is one of the 

 best of our native shrubs for ornamental planting. 



Rocky Mountain Thimble-berry (Rubus parvif torus Nutt.) 



An attractive shrub with erect or drooping stems or eanes, 

 three to eight feet high, and very large five-lobed leaves. It has 



