280 



S. B. PARISH 



Erodium cicularium 

 Erodium moschatum 

 Festuca myurus 

 Hordeum murinum 

 Hordeum pusillum 

 Lamarkia aurea 

 Lactuca scariola var. 

 Lolium perenne 

 Lolium temulentum 

 Marruhium vulgare 

 M edicago denliculata 

 Mentha viridis 

 Melilotus alba 



Nasturtium officinale 

 Polygonum aviculare 

 Polypogon monspeliensis 

 Ricinus communis 

 Rumex crispus 

 Rumex conglomeratus 

 Salsola Kali var. 

 Sisymbrium officinale 

 Stellaria media 

 Silybum Marianum 

 Urtica urens 

 Xanlhium canadense 

 Xanihium spinosum 



The fact that none of the abo^'e plants were observed in the 

 course of two explorations of the whole Valley, in which particu- 

 lar attention was given to the weed flora, is not proof that not one 

 of them has in any place obtained a limited foothold, but it is good 

 evidence that none are, at most, more than merely adventive, and 

 that most of them are absolute!}' absent from the Valle\'. That, in 

 the course of time, the most, if not all of them will be introduced 

 is inevitable. It will be interesting to observe how manj' will 

 adapt themselves to the climatic conditions of the Valley, and to 

 what extent they will prove capable of meeting the competition 

 of the weeds v.'hich alread}' ha\'e possession, and which are 

 suited to the environment in which they grow. Some of the worst 

 have elsewhere proved themselves fulh' capable of enduring desert 

 aridit}', but to others it will probably be prohibiti^'e. 



Bulletin 2i0 of the Agricultural Experiment Station of the Uni- 

 versity of California contains a list of eleven species of Imperial 

 Valley weeds, four of which were not seen in the Valley hy the 

 writer. These are Wild Morning Glory {Convolvulus incanus), 

 Dodder (Cuscutaepiihymum), Foxtail (Hordeum jubatum), and Star 

 Thistle (Centaurea melitensis). Xo particulars are given as to the 

 extent of their occurrence. 



