52 Chapters in Modern Botany CHAP. 



in number and by 150 per cent in total weight, so that, in 

 spite of the relatively enormous quantity of flower-stalk 

 produced by the fed plants during the previous summer, 

 they had still been able to lay up a far greater store of 

 reserve material." 



Similar results were independently reached by Rees, 

 Kellermann, and Von Ra'umer, who used aphides as food 

 for the plants. 



It is noteworthy that the beneficial effect of insect diet, 

 although distinct in the vegetative system, is much more 

 remarkable in relation to reproduction a fact which ex- 

 plains the unfavourable opinion of other observers. 



Other Insectivorous Plants. Besides the apparently 

 indubitable insect-eaters which we have described, there are 

 some in regard to which fuller information is still desirable. 

 Thus not only Dischidia, an Asiatic genus of Asclepiads, 

 whose pitchers contain internal roots, Martynia, one of 

 the Pedalineae, but Caltha diontzfolia, a species of the same 

 genus as our marsh-marigold, and several Aroids have 

 been called insectivorous. Some South American liver- 

 worts (e.g. Anomoclada mucosa and Physiotium cochleari- 

 forme) and a fern (Elaphoglossum glutinosurri) have been 

 described by Spruce as capturing numerous insects. The 

 basally-united leaves of the common teasel {Dipsacus) 

 frequently enclose moats of water in which insects are 

 drowned, and Francis Darwin described protoplasmic fila- 

 ments apparently emitted by the cells of certain glands within 

 these cups, and which he supposed to absorb the products 

 of decomposition. A similar process has been described by 

 Ludwig as occurring in Silphium, a genus allied to the 

 teasel. 



Zopf has recently described an interesting fungus 

 (Arthrobotrya oligospora), which catches small thread- 

 worms in great numbers in its nooses, riddles their bodies 



