EXAMPLES or DROUGHT RESISTANCE. 



19 



annual precipitation is a scant 3^ inches, with a total of only 0.70 

 inch for 1903 and a maximum of 9.36 inches for 1905. (See Table III.) 



Scant as this rainfall is it nearly all occurs in the six months 

 from October to March, inclusive. During the six summer months 

 when a temperature of 100° F. is reached almost daily there is 

 scarcely a trace of rain. (See 

 fig. 4.) That any vegetation 

 should be able to pass through 

 this terrible period of heat and 

 drought seems beyond belief t o 

 one accustomed to the behavior 

 of plant growths of the regions 

 having abundant rainfall; yet 

 many species of shrubs and 

 three species of trees are native 

 in these hot sands. 



That the olive, whose beauti- 

 ful groves are typical of the most 



favored portions of France and Italy, should be able to survive and 

 even successfully compete with these desert shrubs in their own 

 habitat, when planted among them and then abandoned, gives us a 

 new insight into the real character of this tree that makes it worthy 

 of careful study. 



Table HI.— Maximum and viinimum temperatures and preci-pitation at Palm Springs 

 station, four miles north of the Pope olive plantation, California, elevation 584 feet, for 

 the years 1897 to 1907, inclusive. 



MAXIMUM TEMPERATURE (DEGREES FAHRENHEIT). 



Fig. 4.— Diagram showing the mean monthly rain- 

 fall at I'alm Springs station, Gal., as presented in 

 Table III. 



MINIMUM TEMPERATURE (DEGREES FAHRENHEIT). 



1897. 

 1898. 

 1899. 

 1900. 

 1901. 

 1902. 

 1903. 

 1904. 

 1905. 

 1906. 

 1907. 



38 

 30 

 30 

 34 

 30 

 32 

 40 

 32 

 45 

 33 

 30 



32 



48 

 28 

 38 

 44 

 30 

 32 

 39 

 28 



'■io' 



37 



42 

 46 

 50 

 50 

 42 

 4(i 

 49 

 50 

 42 

 42 



40 

 54 

 56 

 42 

 58 

 50 

 50 

 53 

 46 

 50 

 55 



39 



58 

 60 

 52 

 04 

 62 

 54 

 53 

 50 

 58 



65 

 70 

 66 

 60 

 61 

 59 

 60 

 69 

 60 

 62 

 70 



77 

 78 

 8.5 

 69 

 75 

 66 

 05 

 75 

 75 

 84 

 72 



81 

 78 

 70 

 70 

 80 

 68 

 68 

 79 

 80 

 70 



68 

 64 

 70 

 64 

 05 

 (iO 

 58 

 61 

 70 

 62 

 60 



55 

 62 

 50 

 54 



(i5 



m 



58 

 62 

 60 

 47 

 60 



42 

 42 

 50 

 48 

 47 

 .35 

 50 

 56 

 40 

 32 

 46 



30 

 32 

 32 

 44 

 30 

 40 

 34 

 48 

 30 

 40 

 35 



30 

 32 



28 

 34 

 30 

 30 

 32 

 32 

 28 



'30 



192 



