Diomca Muscipula, lillis. 43 



the passage of the sap enclosed within the protoplasmic sac 

 of each cell. 



Were animal histologists agreed as to the minute structure 

 of muscle, and the changes that occur in it during contrac- 

 tion, it might be possible to make some comparison of veget- 

 able and animal contractility. Meanwhile the facts and state- 

 ments to hand, suggest that contractility, alike in the veget- 

 able and animal kingdoms, is accompanied by migration of 

 liquids through the protoplasmic substance, and that this is 

 wholly determined by the molecular condition of the proto- 

 plasm irrespective of cell walls. 



When one attempts to trace how such a complicated 

 mechanism as that of Dioncea leaf has been evolved, difficulties 

 appear on every side. Several definite points, however, may 

 be referred to. From Darwin's first statement to Lindsay's 

 recent one, the poverty of root development has arrested the 

 attention of observers. The writer dug up a lot of plants 

 entire, and carefully washed them. He found that the roots 

 never branch; that from below each cluster of fresh, or 

 recently decayed leaves, three to seven, or in strong plants, 

 nine roots arise; that the average number is four; that the 

 roots are from a half inch to three inches long, according to 

 age ; that the average total length of functional root-system on 

 a plant at any one time, is eight inches, and of this only a part 

 is covered by functional root-hairs. It is a mistake, however, 

 to suppose, as some have done who never visited the locality, 

 that Dioncea usually grows among moist Sphagnum. A very 

 few plants occasionally occur in such situations, but at least 

 seven-eighths grow in a loamy sand. It is a rather significant 

 fact, also, that they often grow in the midst of such plants as 

 Seymeria tenuifolia, Gerardia purpurea and G. tenuifolia, that 

 are equally poor as Dioncea in root development, but have 

 formed strong, parasitic root-suckers, by which they draw sap 

 from the densely interlaced roots of ericaceous shrubs, as well 

 as grasses and other herbs. The fly-catching capabilities of 

 Dioncea, and parasitic connections of Seymeria and Gerardia 

 are parallel physiological advantages that one can vividly see 

 the benefit of for each, when studied in relation to natural 

 surroundings. 



