52 THE BIOLOGY OF HARDING COUNTY 



46. LIXACEAE (Flax Family) 



266 Lin n ni Lcinsii Pursh. Blue Wild Flax. 

 Quite abundant on the plains. 



267 Linum rigidum Pursh. Yellow Wild Flax. 

 Plentiful on the steppe in all parts of this area. 



47. POLYGALACEAE (Milk wort Family) 



268 Polygala alba Nutt. Milkwort. 

 Common on the plains. 



269 Polygala terticillata L. 



Rare on the steppe near Rabbit Butte, Perkins Co. 



48. EUPHORBIACEAE (Snow-on-the-mountain Family) 



*27<D Euphorbia arkansana Engelm & Gray. 

 Tolerably common on the 'steppe. 



271 Euphorbia glyptospenna Engelm. 

 Occasionally on the plains throughout. 



272 Euphorbia petaloidea Engelm. 



Common on the sand along the Moreau River, Boxelder 

 Creek and other streams. 



49. CALLITRICHACEAE 



273 CalUtriche bifid a (L) Morong. Water Star wort. 

 Growing submerged in water ; local in the smaller streams. 



274 CalUtriche palustris L. Water Fennel. 



Partly submerged in shady brooks, West Short Pines. 



50. ANACARDIACEAE (Sumac Family) 



275 Rhus Rydbergii Small? W T estern Poison Ivy. 



Abundant in groves, on rocky slopes, on grassy hillsides in 

 "broken" areas. 



276 Rhus trilobata Nutt. Skunk-Bush. 



Common on hillsides of rougher regions. Not poisonous. 



51. CELASTRACEAE (Staff Tree Family) 



277 Celastris scandcns L. Climbing Bittersweet. 

 Abundant in the wooded gulches of the buttes. 



52. ACER ACE AE (Maple Family) 



278 Acer negundo L. Boxelder. 



Single trees and small clumps are scattered along the streams 

 in the valleys especially about the buttes. 



