iQig] RAMALEY—SACRAMENTO PLAINS 381 



of the more favorable edaphic conditions. The present paper 

 will describe only the undrained depressions. 



Early in March a spring outburst of flowering annuals occurs 

 on the Sacramento plains. A conspicuous flora develops, which 

 continues, with various changes, during two or three months. 

 This vernal meadow-grassland shows great masses of color, due 

 to the flowers of Calandrinia, Eschscholtzia, Platystemon, Trifolium, 

 Orthocarpus, Nemophila, Erodium, Lupinus, Gilia, Brodiaea, 

 Layia, Lotus, Collinsia, etc. Toward the latter part of May 

 these annuals and the various grasses have ripened their seed, and 

 the landscape has become brown. 



The low places in the plains show no fresh vegetation for two 

 or three weeks after the spring outburst takes place in the ordinary 

 grassland, for the ground is still wet and cold. At 2 dm. the soil 

 temperature is 12-15° C, instead of 18-21° as in the vernal meadow. 



The earhest plant of the depressions is the "meadow-foam," 

 Floerkea Douglasii CLimnanthaceae).- This is a succulent herb 

 about I dm. tall, with a profusion of white or roseate flowers. 

 It shows first as a fringe at the margin of low areas, extending 

 around on a contour line and resembling foam on a windy shore 

 (fig. i). Later, as the soil becomes drier and warmer, the meadow- 

 foam works inward, meeting the vegetation that now appears in 

 the central part of the depression. By May i, at Sacramento, 

 the meadow-foam has ceased blooming and has well developed 

 fruits. Not all depressions have the fringe of meadow-foam here 

 described, but very many do. 



Two rather definite areas may be distinguished in the depres- 

 sions. There is a central portion which remains wet for a longer 

 period, and a marginal area around it w^hich merges into the 

 surrounding ordinary grassland. The central and marginal areas 

 have their own characteristic plants. A condensed statement 

 later in this article indicates seasonal differences in the appearance 



of the two areas. 



Central area 



The central area is characterized as a rule by a growth of 

 Allocarya californica, a low, white-flowered borage, or sometimes 

 by other species of the genus. Often the Allocarya forms a close 



