210 ANNUAL EEPORT 



Saxifraga luteo-viridis, S. hulbifera, Sempervivum montanmn, Sapon- 

 aria viscosa, and otliers; also some plants growing near water 

 possess this faculty, as Sedum viUosum. But it would be wrong, 

 to suppose that all plants possessing sticky surfaces ui)on leaves 

 or stems could also absorb the insects caught upon them. In 

 many cases such sticky surfaces are simply protections of the 

 flowers against unwelcome visitors. Glands which secrete such 

 a stibky fluid may be of a twofold benefit to the plant possessing 

 them: They may protect against certain insects, and they may 

 also derive benefit from those killed by this glue. 



Many plants possess upon the upper surface of their leaves pe- 

 culiar organs, looking like glands, but which do not secrete. 

 These organs are there to absorb water, and are of great impor- 

 tance is the economy of plants. They can but seldom absorb' 

 chemically pure water, and nitric acid and ammonia is almost 

 always obtained with rain from the air. This is very important 

 for plants not able to obtain by means of their roots a sufficiently 

 large amount of these substances. Many leaves show peculiar- 

 depressions in which rain is retained for a long time. Dust, 

 small dead animals, pollen, etc., is carried there bythewind^ and 

 the water in these depressions soon becomes discolored and con- 

 tains soluble nitrogenous substances, which are absorbed by suck- 

 ing cells found in the bottom of these receptacles. They are^ 

 therefore, similar to the traps of insectivorous plants, but lack 

 arrangements to invite insects, nor do they prevent their escape^ 

 still they form the connecting links with real traps. 



Venus fly-trap, the best and longest known of carnivorous 

 plants, has recently started quite an animated discussion in scien- 

 tific papers. Gardeners claimed that the eating of animal food 

 was of no benefit to the plants, but was on the contrary quite in- 

 jurious. They found that such plants would thrive without ani- 

 mal food at least as well as with it. Moreover, if fed repeat- 

 edly, the leaves would turn yellow and die. If cheese was used 

 as a food the leaf would hold and dissolve it, but would die in 

 consequence. (The kind of. cheese was not stated.) But we 

 must recollect that plants in their native home are not apt to- 

 overfeed themselves. Larger insects can escape, as we have 

 seen. If we deduct all the hard and insoluble material of the food 

 left behind we perceive that but little albuminous food was 

 really absorbed from their victims. Larger pieces of meat, cheese, 

 white of eggs and other substances used for experimentation are 

 not to be had by a plant in its native home. At all events plants- 



