698 EXPERIMENT STATION RECORD, 



species of poplars tested, the common Lombardy poplar and Pofmlus 

 fremontU, P. monilifera, and P. canadensis are considered the best for 

 alkali soils. The Japanese camphor tree [Camjjliora officinarum) and 

 the strawberry tree [Arhitus luwdo) have grown fairly well on moder- 

 ately strong alkali soils. Of the oaks tested, the cork oak seems to 

 have made very satisfactory growth, although the amount of alkali 

 was not high. The native white oak {Quercns lohata) often grows 

 in strong alkali basins, and it is thought that Q. cerris will prove valu- 

 able under the same conditions. Of the walnuts tested, the English 

 walnut {Juglans regia) is found to withstand alkali very poorly. One of 

 the native species, J. califoDiica, is somewhat more resistant to alkali, 

 while J. nigra makes very slow growth. The pecan ( Carya oUvwformis) 

 withstands alkali and heat better than any of the walnuts with the 

 exception of J. eaUfornlca. ISTearly all of the leading varieties of mul- 

 berries have been tested at the station and found to do fairly well on 

 alkali soils. The American varieties thrive on medium grades of alkali, 

 but are less resistant than the Oriental forms. Most of the Pacific 

 Coast and large-leaved forms of Japanese maple will not grow at the 

 station, the European and silver maples and the Negundos doing 

 fairly well. Of the elms, a slippery elm ( Ulmus fulva) has made the 

 best growth of any of the trees tested. The leaves of Ulmus americana 

 burn badly and the tree does poorly. The various locusts which have 

 been tested make vigorous growth on strong alkali soils. The carob 

 tree {Ceratonia sillqua) is fairly well adapted to resist alkali, and on 

 account of its thick, firm leaves has few e(|uals in enduring the hot 

 sun. It is well adapted to mesa lauds at Santa Monica without irriga- 

 tion, as well as to many of the dry California hillsides. 'Quite a num- 

 ber of species of Eucalyptus have been tested, the most satisfactory 

 of which are U, amygdaJina, E. rostrata, E. riminaUs, and jirobably E. 

 resinifera. On medium alkali soils Grevillea rohnsfa makes a satisfac- 

 tory growth, but on heavier soils the leaves suffer. Among the palms 

 tested the wild date {Phwnix canariensis) and fan palm ( Wasliiiigtonia 

 Jilifera) have proved best on medium-grade alkali soils. Among the 

 conifers there are few found that will adapt themselves to the con- 

 ditions of the alkali. Jimiperus phwnk-ia succeeds fairly well, and 

 Pinus canariensis quite well. Of the California timber trees all except 

 Pseudotsuga donglasii are found very sensitive to alkali. 



Of the shrubs tested, si)ecies of Kunzia, Fabiana, oleanders, crape 

 myrtle, lemon verbena {Aloysia), and smoke tree {Rhus cotinus) have 

 grown well, 



N^umerous vines were tested, and it was found that the fine starch 

 plant from Japan [Pueraria thunbergiana), wistarias, and jasmines, if 

 protected from the full sun, will withstand considerable alkali. The 

 trumpet creeper {Tecoma radicans) is also very resistant to alkali. 



Among the garden plants which grow successfully on strong alkali 

 soils are portulaccas, calandrinas, ornamental-leaved beets, ice plants. 



