42 NATURE OF DESERT PLANTS 



The casting off of the leaves reduces the area of the plant 

 that is exposed to the unfavorable conditions to a minimum. 

 This reduction of the surface is effected in one way or another 

 by a great variety of plants. Much of our spring vegetation 

 is possible by reason of it. The spring beauties, anemones, fawn 

 lilies, jack-in-the-pulpits, etc., practically complete their growth 

 before the larger summer forms appear. During this short period 

 sufificient food is manufactured by the leaves to mature the seeds 

 and fill the storage organs in the underground bulbs and stems. 

 When the larger forms appear later in the season these plants 

 are overshadowed, their leaves wither, and they are reduced to 

 the small bulbs and stems hidden in the earth. In this condition 

 they remain until the next spring when the abundance of stored 

 food enables them to complete their growth before other com- 

 peting forms appear. 



This ability to reduce the surface of the plant body makes 

 possible the existence of much of the plant life of arid and desert 

 regions. During the short rainy seasons the stored foods enable 

 the plant to quickly put forth the leaves which in turn manu- 

 facture the foods which are stored in seeds, stem and roots. 

 Then practically all trace of these plants is destroyed by the 

 drought. Only the seeds or a greatly reduced portion of the 

 plant remain alive and this is often further protected by being 

 hidden in the ground. A return of favorable conditions quickly 

 awakens these plants to growth. Mr. Dan Beard relates an 

 interesting experience in the desert regions of Texas that illus- 

 trates this feature of plant life. At the close of the dry season 

 this territory was a bare, sun-cracked plain swept by hot, dry 

 winds. Not a green leaf was to be seen. Heavy rains trans- 

 formed this level tract of land into an inland sea. In a few days 

 the water disappeared and one morning he was surprised to see 

 green blades appearing everywhere and in a few days the barren 

 earth was covered with an almost tropical profusion of vegeta- 

 tion of bright flowers. Many desert plants to be sure develop 

 permanent aerial parts but here, too, the most striking feature 

 is the extreme reduction of the organs. Compare the areas of 



