6 



THE AMERICAN BOTANIST 



peculiar ridg}^ surface of ash, elm or oak. The ridgy kinds of 

 bark are so many and so diverse that a special nomenclature 

 has been created by foresters and tree students for describing 

 them. This takes intO' account the height and width of the 

 ridges as well as the depth and shape of the circumscribed 

 spaces between them. Again, one must note whether the pro- 

 jections are more or less parallel or to what "degree they inter- 

 lace, bisect, or cross each other. Thus we may have a diamond 

 or triangular or checker-board pattern. ■ Absolutely no two 

 trees are alike in their bark and we may add that no two indi- 

 viduals even of the same species are alike. 



XEROPHYTES 1 



By Willard X. Clute. 



T T is impossible for plants to live without water, but the 

 xerophytes come pretty near to accomplishing it. A plant 

 that can get along for twenty-five years without fresh supplies 

 of moisture, seems practically independent of soil water or 

 rainfall. All ordinary plants must have a perennial supply 

 of moisture or they die. Let the rains hold off until they have 

 sucked the water from the soil and they wither at once, but 

 a little thing like lack of rain does not bother the xerophyte. 

 Its very name, in fact, means drought plant, and the fortitude 

 with which it endures a dry season that would put our worst 

 weeds out of business is eloquent testimony to the effectiveness 

 of the devices for retaining water with which it is equipped. 

 A xerophyte is Nature's last word in the conservation of 

 water by plants. 



Xerophytes are usually regarded as inhabitants of deserts, 

 but not all the plants in deserts are xerophytes. nor do all 

 xerophytes live in deserts. There are no deserts in which no 



