ECONOMIC PLANTS WORTHY OF INTRODUCTION. 13 



methods of cultivation which have been brought about by political 

 conditions — the vicissitudes of war, the continual migration of tribes, 

 and colonization — all acting through such long periods of time, we 

 can readily understand why so many varieties of cultivated plants 

 have been developed and why the country is such an interesting one 

 to study and is so full of promise. 



ECONOMIC PLANTS WORTHY OF INTRODUCTION INTO THE UNITED 



STATES. 



PLANTS RECOMMENDED AS STOCKS. 



Zizyphus 8pina-christi (Christ-thorn) . — This tree averages 16 feet 

 or more in height, with a diameter of 16 to 24 inches. Its fruit, 

 about the size of a hazelnut, is not so well liked as that of the species 

 mentioned later. It is a tree which is found along the coast and 

 in the valley of the Jordan. There are several local races adapted to 

 different life conditions. In the valley of the Jordan, and especially 

 farther south in the valley of the Arabah, it is the most common 

 tree on alkaline soils. 



The Arabs water their land very abundantly and do not provide 

 any drainage, and as a consequence great quantities of alkaline salts 

 are brought to the surface. At the end of two or three years the soil 

 is so excessively salty that the land is abandoned for a number of 

 years until the rains have washed the salt down into the subsoil. 

 Zizyphus spina-christi grows on these lands abandoned on account 

 of their excessive alkalinity, so that when an explorer finds a field 

 overgrown with this plant he can be sure that it has formerly been 

 under cultivation. 



Zizyphus spina-christi inermis. — In very moist lands along the 

 banks of streams, for example those of the Jordan near Jericho, the 

 type plant loses its thorns (thorny stipules or stipular spines). The 

 resulting variety is called inermis (spineless). 



Ziz,yphus lotus. — This bush rarely grows to a height of 6 feet. It 

 tends rather to give off suckers, thus spreading continually and form- 

 ing clumps of large diameter. This characteristic makes the plant 

 very valuable for the fixation of dunes. It seems to be more particu- 

 larly adapted to inland dunes, although it has been grown success- 

 fully along the coast. The fruit of this species, although smaller 

 than that of Z. spina-christi, is more palatable and, under the name 

 of " Dom," is eaten dry by the Arabs throughout the valley of the 

 Jordan, and also by the Jews of Tiberias. The taste is a little like 

 that of dried apples. 



Zizyphus lotus seems to be less adapted to alkaline ground than 

 Z. spina- -christi, but grows on the most arid hills. In the vicinity 

 of Tiberias and farther south and east it is the only bush which 



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