230 



BOTANY 



PART 1 



by plants, those exhibited by Carnivorous or Insectivorous Plants in 

 the capture and digestion of animal.-; are unquestionably the most 

 curious. Although they are green plants and able to manufacture 

 carbohydrates for themselves they have, in addition, secured for 



themselves, by peculiar con- 

 trivances, an extraordinary 

 source of nitrogenous organic 

 matter, by means of which 

 they are enabled to sustain a 

 more vigorous growth and 

 especially to produce more 

 seeds than would otherwise 

 be possible without animal 

 nourishment. 



It is not accidental that the plants 

 which have become carnivorous are, 

 for the most part, either inhabitants 

 of damp places, of water or swamp*. 

 and moist tropical woods, or that 

 they are epiphytes. The nitrogenous 

 and phosphoric salts of the soil are 

 not obtained by them in the same 

 quantities as in the case of the more 

 vigorously transpiring land plants. 

 This is very evidently the case iu 

 the Sundew (Droscra), which is 

 loosely attached by a few roots upon 

 a thick spongy carpet of Bog-nio-s 

 and must find in the animal food a 

 valuable addition to its nitrogenous 

 nourishment. 



A great variety of contrivances 

 for the capture of insects are made 

 use of by carnivorous plants. The 

 leaves of Drosera are covered with 

 stalk-like outgrowths ("tentacles "), 



the glandular extremities of which 



Fio. 200. tfummxata iourUwta. showing the entrance ,. , -j -j A - 



to the hollo* tetemodT (From Scrap** <l" cl ' ar g e a VISCld acld secretion 

 I'l.mt-Geography.) (Fig. 208). Any small insect, or even 



larger fly or moth, which comes in 



contact with any of the tentacles is caught in the sticky secretion, and in its in- 

 effectual struggle to free itself it only comes in contact with other glands and is 

 even more securely held. Excited by the contact stimulus, all the other tentacles 

 curve over and close upon the captured insect, while the leaf-lamina itself becomes 

 concave and surrounds the small prisoner more closely. The secretion is then dis- 

 charged more abundantly, and contains, in addition to an increased quantity of 

 acid, a peptonising ferment. The imprisoned insect, becoming thus completely 

 covered witli the secretion, perishes. It is then slowly digested, and, together 

 with the secretion itself, is absorbed by the cells of the leaf. 



