1879. 



AND HORTICULTURIST. 



119 



CARNIVOROUS PLANTS. 



BY THOS. FOllFAU, WOBURN, ONTARIO, CAN. 



In the February number of the Gardener's 

 Monthly I see that Mr. C. W. Seelye and Prof. 

 Beal criticise the result, or ratlier the statement 

 of the result of Mr. Henderson's experiments on 

 Diontea muscipula. To my mind these experi- 

 ments of Mr. Henderson's are not entirely satis- 

 factoiy, from the fact that he appears to have 

 tried them in one way only : that is by feeding 

 the plants with flies, &c., and comparing them 

 with plants not so fed. Now the Messrs. Dar- 

 win tried a vast number of experiments in many 

 different ways ; still they relied to a great ex- 

 tent on litmus paper as a positive proof that the 

 food was consumed. 



It so happens that we have growing wild in 

 this neighborhood thousands of Drosera rotundi- 

 folia, and I have amused myself in trying a few 

 experiments and closely watching the habits of 

 the animal (as Mr. Darwin almost makes it out 

 to be), in its native home. I first procured a 

 few plants and potted them. After they had 

 become thoroughly established in the pots, I 

 commenced to feed them with insects of differ- 

 ent species, large insects dead and smaller ones 

 alive. Insects as large as the common house fly 

 must be killed, as their strength is greater than 

 that of the glandular hairs of the trap, and they 

 would escape ; but small insects such as mosqui- 

 toes if once in the trap are forced to stay there. 

 Whenever I fed a dead insect to a plant I placed 

 another of the same size and species in some se- 

 cure and similar situation. By this I found that 

 it took exactly the same time for the atmosphere 

 to consume an insect as it took the Drosera, 

 providing the temperature and moisture were 

 the same. I then tried the same experiment 

 on the wild plants with the same results. I 

 next examined the wild plants and found that 

 about fifteen per cent, contained insects and their 

 remains, about twenty-five per cent, contained 

 extraneous vegetable matter, the remaining sixty 

 per cent, nothing. I could see no difference in 

 size or luxuriance of growth between those con- 

 taining insects and those containing vegetable 

 matter ; but those containing nothing whatever 

 were generally smaller. This I accounted for 

 by supposing that the latter were younger plants, 

 and had neither the surface exposed to catch nor 

 the strength to hold extrenuous matter that the 

 former had. I have read somewhere that if a 

 piece of wood or other uneatable substance be 



placed within the opening of the glandular hairs 

 of the Dionrea the hairs would immediately 

 close on the substance, but on this being re- 

 peatedly done this closing would cease, the 

 plant having found from experience that hard 

 substances were unpalatable. This I tried with 

 the Drosera rotundifolia, but whether my plants 

 being Canadian were sharper, or that they were 

 not in the habit of doing such outlandish tricks, 

 they could not be fooled in that way, no move- 

 ment of the hairs being perceptible. A small 

 insect placed within the opening was completely 

 entrapped but I could see no movement of the 

 hairs whatever. The insect, if alive, would die 

 in from twenty minutes to half an hour. Death 

 appeared to take place by suffocation from the 

 clammy fluid exuding from the glands — similar 

 to what would take place if the insect had been 

 covered with oil or honey. 



Prom this and other simple experiments, and 

 from what I can find to read on the subject, I 

 have come to the following conclusions : 



1. That the Messrs. Darwin are correct in say- 

 ing that the Drosera rotundifolia is carnivorous. 

 2. That Mr. Henderson is correct in saying that 

 no perceptible difference could be seen in the 

 plants he fed and those not so fed. 3. That 

 Prof. Beal's idea that petunias, myrtinias, &c., 

 are carnivorous is also correct. 4. That all 

 plants are carnivorous. 



The theory by which I make everybody right 

 and nobody wrong is this : We know that all 

 plants absorb food in the form of carbonic acid, 

 ammonia, &c., through their leaves. We also 

 know that animal or vegetable matter such as 

 beef tea, dead insects, or decaying leaves if al- 

 lowed to become putrid, throw off a large amount 

 of ammonia, &c. ~Eo-w if we place any such 

 putrid substance in sufficient quantity in close 

 proximity to any plant, we know that such plant , 

 will be benefitted greatly. I apprehend that if 

 Mr. Henderson fed each of his Dionaea plants 

 nearly every day he must have removed the in- 

 sects given the day before ; consequently it could 

 have given off little if any of its gases. Or per- 

 haps he only examined the plants each day and 

 replaced such insects as had decayed. If such 

 were the case each plant would only have re- 

 ceived the full benefit of the gases from proba- 

 bly four or five insects during the three months 

 of trial. In either case the benefit would be im- 

 perceptible. 



In Mr. Darwin's test by litmus paper it is 

 quite probable that the reception by his Droseras 



