244 standley: floras of new Mexico and Argentina 



Lolium italicum A. Br. 

 Notholcus lanatus (L.) Nash 

 A triplex hortensis L. 

 Amaranthus deflexus L. 

 Brassica napus L. 

 Brassica nigra L. 

 Cer ostium vulgatum L. 

 Medicago denticulata Willcl. 



Medicago orbicularis All. 

 Conium maculatum L. 

 Daucus carota L. 

 Veronica peregrina L. 13 

 Dipsacus fullonum L. 

 Lactuca scariola L. 14 

 Centaur ea melitensis L. 

 Cirsium lanceolatum (L.) Scop. 



Several of these European plants, notably Dipsacus fullonum, 

 Centaurea melitensis, Hordeum murinum, Medicago sativa and 

 M. denticulata, Melilotus indica, Marrubium vulgar e, Er odium 

 cicutarium, and Sonchus asper, are either confined in the United 

 States to the Southwest or else are particularly abundant there, 

 and are known to have occurred in that region at an early date. 

 It is probable that they reached the United States through the 

 same agency by which they were transported to Argentina — the 

 early Spanish settlers. 



While some of the European plants cited have become widely 

 scattered with the development of international commerce, many 

 thrive only in temperate regions, and several of them, like the 

 Salsola, Erodium, Hordeum, and Centaurea, seem to thrive best 

 in arid or subarid regions. These adventive plants, combined 

 with the more than slightly familiar aspect of the native flora, 

 would make a botanist accustomed to our Southwestern vegeta- 

 tion feel very much at home when he first made the acquaintance 

 of the Rio Negro Valley of Argentina. 



13 In New Mexico we have V. xalapensis H.B.K. as a native species. While 

 all botanists may not consider it specifically distinct from V . peregrina, it cer- 

 tainly is distinguished readily from the naturalized European plant. 



14 In New Mexico only L. integrata (Gren. & Godr.) A. Nels. is known. It is 

 often considered a subspecies of L. scariola. 



