Euphorbia 



EUPHORBIACEAE 



645 



o 55 



Map 1337 



Euphorbia dentata Michx 



Map 1338 

 Euphorbia heterophylla L 



roadsides, in fallow fields, and rarely in open woodland. This species is no 

 doubt adventive from the west. It was unknown to our earlier botanists. 



The leaves vary in width and a narrowleaf form has been named. 



Pa., S. Dak. to Wyo., southw. to Tenn., La., and Mex. 



11. Euphorbia heterophylla L. (Poinsettia heterophylla (L.) Kl. & 

 Garcke.) Painted Spurge. Map 1338. This species is doubtless adven- 

 tive in our area. Along railroads and roadsides and in waste places. 



This plant much resembles the preceding but can be separated from it 

 by its alternate leaves, glabrous stem and leaves. The leaves of Euphorbia 

 heterophylla vary from almost linear to fiddle-shaped. 



Ind. to S. Dak., southw. to Fla. and Tex. 



12. Euphorbia obtusata Pursh. (Tithymalus obtusatus (Pursh) Kl. & 

 Garcke.) Map 1339. I have this species from the dry, wooded bank of the 

 St. Mary River south of Fort Wayne, from along the Wabash River east 

 of Bluffton, and from the roadside on the south side of Half Moon Pond 

 about 10 miles southwest of Mount Vernon, Posey County. Madge McKee 

 collected it in Newton County. It was collected in Tippecanoe County by 

 Young and the specimen is in the herbarium of Indiana University. 



Pa. to Iowa, southw. to S. C. and Tex. 



13. Euphorbia Esula L. (Euphorbia virgata Wald. & Kit. in Rhodora 

 39: 50. 1937 and Tithymalus Esula (L.) Hill.) Leafy Spurge. Map 

 1340. This species has been reported as an escape, etc., in three counties. 

 Hansen (Proc. Indiana Acad. Sci. 37: 320. 1928) says: "Specimens were 

 collected in full flower near Winamac, where it is established along road- 

 sides, on June 20, 1927." W. N. Clute informed me in 1936 that there is 

 "a large colony along the canal in Indianapolis between Illinois and Meri- 

 dian Streets." In 1937 I found it abundant over an area of 3 acres in a 

 pasture about 3 miles southwest of Knox, Starke County. 



Leafy Spurge is a very obnoxious weed and spreads rapidly. Its roots 

 penetrate the soil to a depth of 5-15 feet. On account of the acrid latex 



