288 INSECTIVOROUS PLANTS. [Feb. 



country since 1765; for in that year Ellis, a well-known English 

 naturalist, sent a drawing of it to Linn;eus, who bestowed on it the 

 poetical name of Diona3a. The account which Ellis gave of it moved 

 the great Swedish naturalist to declare that, though he had seen and 

 examined no small number of plants, he had never met with so 

 wonderful a phenomenon. Ellis shortly afterwards obtained living 

 plants from America, which he grew and flowered in his own rooms. 

 He also noted, or rather suspected, tlie insectivorous propensities of 

 this plant. A leaf of Diontea is somewhat like that well-known 

 instrument, a rat-trap ; it is, however, a much more refined piece of 

 mechanism. It consists of a blade or leaf stalk and a two-lobed 

 leaf ; in the interior there are three sensitive filaments on each lobe. 

 When any of these are touched, however lightly, the two lobes 

 immediately close together, and the marginal spines interlock 

 through. At first they do not close tight, but leave a small opening. 

 This puzzled Mr. Darwin very much. He afterwards found that 

 the object the plant has in view, is simply to allow of the escape of 

 small insects that could be of little use, retaining only those that 

 would be of some service. When a moderate-sized fly is enclosed, 

 in its struggles to escape it irritates still more the sensitive hairs, 

 which ultimately causes the lobes of the leaf to press tighter. Then 

 and not till then a true digestive fluid is poured out from numerous 

 glands with which the leaf is studded, and the' product is absorbed 

 through the lobes of the leaf. Diona;a is able to digest very much 

 the same substances in exactly the same way that the human 

 stomach does. The time taken to digest a fly varies according to 

 the vigour of the plant ; about eight days is the usual time taken 

 by a healthy plant to consume a respectable fly. The marginal 

 spines then become erect, and the leaf ultimately expands, ready for 

 another meal. If we try to deceive it, by putting in some sub- 

 stance from which it cannot derive any nourishment, such as small 

 bits of wood or glass, the leaf closes, as it does by the mechanical 

 irritation of touching, but in less than twenty-four hours will be 

 found open and the indigestible substances thrown out. 



THE LENTIBULACE^E OR BUTTEKWORT FAMILY 



contains Pirguicula or Butterwort and Utricularia or Bladderwort. 

 Pinguicula captures insects by the ujjper surface of its leaves. 

 These are set with glandular hairs which secrete a viscid fluid. 

 Like Drosera, this plant digests and absorbs nitrogenous matter. 

 Utricularia captures insects by the small bladders attached to the 

 root-like processes. These bladders possess a most ingenious trap- 

 door mechanism, which only open inwards, so that when a cyclops 



