26 BOTANICAL GAZETTE [JULY 
channels, sloughs, and low islands. By extensive dredging and 
levee work much of this extremely fertile country has been reclaimed 
and brought into cultivation. The soil is a mixture of peat and 
- 
SACRAMENTO 
VALLEY 
SAN JOAQUIN 
VALLEY 
Fic. 3.—Map of central California, showing asparagus districts. 
river sediment in various proportions, from almost pure formations 
of each to an equal mixture of the two. After reclamation and con- 
tinued cultivation the level of these islands gradually sinks, and 
they become saucer-shaped, several feet below the river level outside 
