Water Ctltures. 249 



The Arizona cypress {Ciipressiis arizonica) abounds in 

 the canyons down to the levels of 4000 feet and is success- 

 fully cultivated in Tucson and elsewhere. The desert willow 

 {Chilopsis linearis) also brings its abundant violet colored 

 flowers to bloom during the season, later ripening a wealth 

 of seed which seem to be capable of wide dissemination. The 

 sanco, or elder {Samhucus glaiica) becomes a tree with a 

 height of 30 or 40 feet being characterized by the growth 

 of a number of adventitious branches on the lower parts of its 

 grayish trunks. Among the most graceful trees of the region 

 are the ashes, the three species of which show spreading 

 crowns and graceful branches giving the effect of a New 

 England elm. These trees attain notable size along stream- 

 ways. A hackberry {Celtis reticulata) frequents the same 

 regions as the ash, becoming a goodly tree, while a shrubby 

 relative forms dense clumps ten feet in height and of the same 

 diameter on the slopes and plains, being known locally as the 

 garamboya. Three species of Lycium open inconspicuous 

 flowers and mature fruits in the summer, both the sucqulent 

 leaves and fruits being greedily devoured by birds and 

 rodents. 



Ihe ocotillo, {Foiiqiiieria splendens) displays the ter- 

 minal racemes of bright flame-colored flowers which tip its 

 diverging branches early in May, and the capsules open to 

 spread the fuzzy winged seeds by the end of the month. 

 Germination quickly ensues producing a stem but 2 or 3 inches 

 in length, which ceases to elongate and lateral branches arise 

 attaining slender divergent lengths up to 6 or even 25 feet, 

 giving the plant a very striking appearance. 



WATER CULTURE METHOD FOR EXPERIMENT- 

 ING WITH POTATOES. 

 By J. J. Skinner. 

 In greenhouse and laboratory investigations of some 

 potato soils, conducted by the Bureau of Soils, U. S. Depart- 

 ment of Agriculture, water cultures were used quite exten- 



