I 'LATE 5 



Kg. I. Looking north over the flood plain of the Chemehuevis Valley, 

 California side. At this date (March Id, l!MO) only the cottonwoods had come 

 into leaf. This is the typical willow -Cottonwood association of the riparian 

 bell as found in all the broad valleys. The component plants are willows, of 

 two apecies, Cottonwood, guatemole, and screw bean. Some of the latter show 

 in the foreground because of the mistletoe clumps in their as yet leafless 

 branches. At the time of taking this picture birds of the winter visitant 

 category were plentiful (see text, p. 71). 



Pig. 5. The arrow weed association, the typical clement in which is the 

 arrow-weed (Pluchea sericea). This plant forms an almost continuous growth 

 over the river Hood plain outwardly adjacent to the willow cot tonwood asso- 

 ciation. Animal life was poorly represented in this association as compared 

 with any other of the region. Those birds and mammals found therein 

 appeared nearly all to traverse it only incidentally, in passing between the 

 mesquite and willow associations. Photograph taken near Pilot Knob. May 



11, nun. 



[278] 



