OCR Text |
Show PLANTS OF ARID REGIONS. Tender Growths That Survive Long Periods of Severe Drought. Even tho deserts havo their botany, as ho desert botnnlcal laboratory at Tucson, Ariz, Is ultncbu. The water relations of tho plants of arid regions so delicately are adjusted that a slight vurlatlon In the avallablo supply or In the rem tho humidity of the ulr pro-duces pro-duces a quick and notublo effect. A shrun called the ocotlllo had been without with-out .cuves for several weeks, owing to a long period of drought. One day three gallons of water woro poured slowly In tho ground at tho base ol tho plant; next day leuf buds were observe!, ob-serve!, which by tho afternoon of the next Cu) had become an inch long, and four dJjs afterward were full grown. Tho period of activity of plants depends de-pends on tho period during which they rotalu their leaves. In tho case ot desert plants growing under adverse ' condition to the large amount of moist- uro present in the air, which .retards transpiration and thus assists tho plant In reserving to some extent tho amount of water at its disposal, it Is considered consid-ered probable that tho leaves absorb ntmospherio ntmosphero in sulTtclent quantity to be of biological importance. impor-tance. It has been proved that Btems of ocotlllo absorb both water and atmospheric at-mospheric molsturo; it also has been bhovwi that u branch of ocotlllo without' with-out' Hives tan absorb a sufficient amount of water to Induce the formation forma-tion of leaves |