16 DROSERA ROTUNDIFOLIA. [Chap. I. 



were compared by number, weight, and measurement, with the 

 following striking results : 



SUured. Fed. 

 Weight (without flower-stems) ... 100 121.5 



Number of flower-stems . 

 Weight of stems 

 Numljer of capsules . 

 Total calculated weight of seed 

 Total calculated number of seeds 



100 164.9 



100 231.9 



100 194.4 



100 379.7 



100 241.5 



These results show clearly enouph that insectivorous 

 plants derive great advantage from animal food. It is of 

 interest to note that the most striking difference between the 

 two sets of plants is seen in what relates to reproduction t. e. 

 in the flower-stems, the capsules, and the seeds. 



After cutting off the flower-stems, three sets of plants were 

 allowed to rest throughout the winter, in order to test (by a 

 comparison of spring-growth) the amounts of reserve ma- 

 terial accumulated during the summer. Both starved and 

 fed plants were kept without food until April 3rd, when 

 it was found that the average weights per plant were 

 100 for the starved, 213.0 for the fed. This proves that 

 the fed plants had laid by a far greater store of reserve 

 material in spite of having produced nearly four times as 

 much seed. 



In Kellermann and Von Raumer's experiments (loc. cit.) 

 aphides were used as food instead of meat a method 

 which adds greatly to the value of their results. Their con- 

 clusions are similar to my own, and they show that not 

 only is the seed production of the fed plants greater, but 

 they also form much heavier winter-buds than the starved 

 plants. 



Dr. M. Biisgen has more recently published an interesting 

 paper" on the same subject. His experiments have the ad- 

 vantage of having been made on young Droseras grown from 

 seed. The unfed plants are thus much more effectually 

 starved than in experiments on full-grown plants possessing 

 already a store of reserve matter. It is therefore not to be 

 wondered at that Biisgen's results are more striking than Kel- 

 lermann's and Von Raumer's or my own thus, for instance, 

 he found that the " fed " plants, as compared with the starved 



" *' Dl* BMentvng des Insectfanges fUr Droaera rotundifolia (L.)," 

 Bot. Zeltung.' 188a 



