standley: floras of new Mexico and Argentina 243 



Before finishing his comparison of these floral areas, the writer 

 feels it desirable to make some mention of the adventive and nat- 

 uralized plants of the Rio Negro Valley represented among Mr. 

 Fischer's collections. Of the native Argentine species two are 

 of interest to United States botanists because they have become 

 more or less naturalized in this country. Poinciana gilliesii 

 Hook., the bird-of-paradise bush, is one of the commonest cul- 

 tivated plants of the arid southwestern United States and of 

 Mexico, and is often found as an escape from cultivation. Ama- 

 ranthus crispus (Lesp. & Thev.) A. Br. has been collected at 

 Albany and New York City, New York, at Wilmington, North 

 Carolina, and at Mobile, Alabama. It was described originally 

 from plants adventive in France, and only in very recent years 

 has it been ascertained that its native habitat is Argentina. A list 

 of the more noteworthy plants adventive in Argentina, as shown 

 b} r the present collection, is as follows: 



Agrostis alba L. 

 Dactylis glomerata L. 

 Holcus halepensis L. 

 Hordeum murinum L. 

 Phleum pratense L. 

 Poa annua L. 

 Polygonum aviculare L. 

 Rumex crispus L. 

 Atriplex rosea L. 

 A triplex semibaccata R. Br. 

 Salsola pestifer A. Nels. 

 Portulaca oleracea L. 

 Bursa bursa-pastoris (L.) Web. 

 Sisymbrium altissimwn L. 

 Medicago lupulina L. 

 Medicago saliva L. 



Melilotus alba Desr. 



Melilotus indica (L.) All. 



Trifolium repens L. 



Tri folium pratense L. 



Erodium cicutarium (L.) L'Her. 



Convolvulus arvensis L. 



Marrubium vulgare L. 



Plantago lanceolata L. 



Cichorium intybus L. 



Sonchus asper (L.) Hill 



Sonchus oleraceus L. 



Taraxacum taraxacum (L.) Karst. 



Xanthium spinosum L. 



Anthemis cotula L. 



Senecio vulgaris L. 



All of the above are Old World plants which occur in New 

 Mexico, and many of them are common in the irrigated lands of 

 the Mesilla Valley. In addition, the following species may be, 

 mentioned which have become established in the Rio Negro Val- 

 ley but are not known from New Mexico, although they have be- 

 come established elsewhere in the United States, most of them in 

 the Southwest: 



