WHAT ARE ADAPTATIONS? 



31 



stem covered with a hard and corky covering which 

 keeps the water in. By doing away with leaves entirely, 

 the green stem instead of the leaves takes on the work 

 of food manufacture. The plant is protected by its spines. 

 No animal will eat it and it produces its young either by 

 seeds or by means of buds from the parent plant. The 

 cactus has solved its problems of life by means of its 

 adaptations. 



Success for Plants and Animals Comes through Adap- 

 tations. You all know how difficult it is to get rid of 

 weeds in a garden. It seems as if they come up over 

 night and that as soon as you pull one up, another takes 

 its place. Weeds are successful plants, but why? If 

 you examine a full-grown weed carefully, you will soon 

 see why. Usually they produce very many seeds, and 

 they have excellent means of scattering them. Look at 

 the tumble weed as it rolls along, dropping seeds as it 

 goes. Look at the dandelion or thistle with its seeds 

 sailing through the 

 air or the stick- 

 tight or cocklebur, 

 with its fruits get- 

 ting a ride by stick- 

 ing to animals. 

 Then weeds produce 

 many more seeds 

 than other plants. 

 Sometimes a single 

 plant forms hun- 

 dreds of thousands 

 of seeds. The seeds 

 sprout under con- wngm pierce 



ditions Unfavorable This cactus has been cut so as to show the watery 



for ntViPr rJnnta pulp which is hel d inside the hard skin. What 



plants takes the place of the leaves in this plant? Why 

 With which they are there no leaves? 



