Flora of Denver. 45 



POLYGONACE^E. (Buckwheat Family.) 



359. Eriogonum heracleoides NUTT. Clusters in com- 

 pound umbels with the rays often branched, flowers yellow, 

 smooth. Clear Creek, found by Miss E. Eaton. Summer. 



360. Eriogonum annuum NUTT. Entire plant white, tall, 

 sometimes branching but usually simple to the cymose clus- 

 ters. Common on the plains. Summer. 



361. Eriogonum cernuum NUTT. Diffusely branching, 

 clusters numerous on deflexed pedicels, flowers white, becom- 

 ing pink. Near Valverde on the Denver and Rio Grande 

 railroad track. Summer. 



362. Eriogonum microthecum NUTT. var. effusum TORR. & 

 GRAY. Low, branching from a woody base, cyme of small 

 clusters very much branched. Common on the plains. Fall. 



363. Rumex venosus PURSH. Easily distinguished by the 

 large rose colored veiny valves and the thickly clustered flow- 

 ers. Near Cherry Creek, North Denver. Early summer. 



364. Rumex salicifolius WEINMANN. The common narrow 

 leaved Rumex. Common. Summer to fall. 



365. Rumex Acetosella L. The common sorrel. Intro- 

 duced. Not common. 



366. Polygonum erectum L. Branches leafy to the sum- 

 mit. 



367. Polygonum ramossfssimum MICHX. Branching 

 above, yellowish, upper leaves bract-like. 



368. Polygonum tenue MICHX. Slender and rather low, 

 spikes distantly flowered. In wet places. Valverde. Fall. 



369. Polygonum aviculare L. (KNOT-GRASS) The very 

 common introduced prostrate Polygonum. 



370. Polygonum Pennsylvanicum L. Stems very tall, 

 five or six feet and leafy, upper part covered with glandular 



