100 DICOTYLEDONS 



These plants find very little food on the rocks, and have rto develop 

 their various organs within a few weeks as they cannot livp when tlie 

 rains are over. I 



The following are their adaptations for a life under such adverse 

 conditions: — 



(a) Their seeds are extremely small, they fall into the crevices of 

 the rocks and germinate when the rains begin. 



(b) The plants remain small (one to two inches high) and groiv 

 quickly, producing flowers and seeds in a few weeks, so that all is 

 ended when the rains cease. 



(c) The want of mineral food is compensated for, at least in some 

 of them, by animal food. We have seen how Utricularia catches 

 animals and feeds on them. Drosera or SundcAv (fig. 94) is also an 

 insectivorous plant, but has other organs to catch insects. The linear 

 leaves of this tiny plant seem to be decked with little diamonds, re- 

 flecting the light of the sun like little dew-drops. There is a sparkling 

 and shining about them like that of the most beautiful brilliant. These 

 sparkling diamonds are little drops of slime, a sticky mass which can 

 be drawn into long threads when touched with the finger — secreted 

 by numerous hairy glands with which the leaves are covered all 

 over. What is the use of these glands? A swarm of tiny midges is 

 dancing over the rock. One of them has left its gay society seeking a 

 resting place. The shining drops, seemingly of honey, have allured 

 the animal to alight on the plant. Instantly it becomes aware of its 

 error and tries to fly away. But alas! its legs stick to the gummy 

 liquid, and if it succeed in setting free one or two legs, in the next 

 moment its other parts, head and wings, get again into the fearful 

 slime, and all its desperate struggling has onlj^ the result that more 

 glands bend over and fasten on it. This is carried to such an extent 

 that the whole blade of the leaf occasionally doubles over. The whole 

 animal is now covered with the slimy fluid secreted by those glands. 

 It dies, and the soft parts of it are in course of time digested by the 

 liquid which is slightly acid, as can be told by testing it with blue 

 litmus paper. After the plant has thus absorbed its animal food, the 

 leaf is unfolded, the hard skeleton of the dead animal soon dries and 

 is carried away by the wind; and the glands shine as before till 

 another careless fly, or a thirsty little caterpillar, or a small butterfly 

 sits on them and runs into death. Larger insects are not caught, as 

 they are strong enough to make their escape from the tentacles of 

 the plant. 



