13 

 A NEW SPECIES OF EUMEX FEOM COLOEADO. 



By Geo. E. Osterhout. 



From all the information I can gather I judge, that I have 

 an undescribed species of Eumex from the higher mountains 

 of northern Colorado, a description of which is here given. 



Rumex densiflorus. Perennial, glabrous ; stem erect, 

 not branched, grooved, ^ to 1 m. high from a stout rootstock 

 and bearing several leaves. The lower and root leaves are on 

 long petioles, cordate at base, some of them large, from 10 

 to 15 c. m. wide and from 1^ to 3 d. m. long, usually rounded 

 at the apex, but occasionally tapering and pointed, the veins 

 radiating at an angle of 70 deg. to 80 deg. from the midrib; 

 the upper leaves are smaller, ovate to oblong on shorter 

 petioles. The dense clusters of flowers are polygamous or 

 dioecious terminating the stem, and on branches from the 

 axils of the upper leaves; the calyx is often red and the 

 anthers brown, giving a reddish brown appearance to the 

 inflorescense. 



The fruit is tinged with red, the calyx wings broadly ovate 

 about 5 m. m. wide by 6 m. m. long, not grain-bearing, retic- 

 ulate veining and without a noticeable midnerve, their edges 

 slightly toothed or entire; the pedicels 1 to l-§ times the 

 length of the calyx wings. The achene is ovate, pointed, 

 dark ash colored, 2 m. m. wide by 3 m. m. long. 



It is possible that this species has been joined with R. 

 occidentalis Watson and some of the differences may be here 

 noticed. R. occidentalis has a vertical root ; this species has 

 a strong root-stock— in the specimen which I have it is seem- 

 ingly horizontal — , and the plants are found in clusters. The 

 calyx- wings of the fruit are without the distinct midnerve 

 of R. occidentalis, and the achene is ovate, not oblong, and 

 lighter in color than that of R. occidentalis. 



I noticed R. densiflorus the past summer at and near 



Erythea, Vol. VI., No. 2 [17 February, 1898.] 



