44G JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



nervous system, and the fact of plants sleeping is one proof of the existence 

 of a nervous system in the members of the vegetable kingdom. Plants 

 sleep at various hours, and not always at night. Light and heat appear 

 to have, in many instances, little to do with plants sleeping, as different 

 species go to sleep at different hours of the day. Thus the coming Morning 

 Glory, Ipomo&a purpurea syn. Convolvulus purpurcus, opens at dawn ; the 

 Star of Bethlehem, Ornithogalum umbellatum, about ten o'clock ; the 

 Goat's-beard, Tragopogon pratensis, opens at sunrise and closes at mid-day, 

 and for this reason is also known as 1 Go-to-bed-at-noon.' The flowers of 

 the Evening Primrose, Oenothera biennis, open at sunset, and those of the 

 night-flowering Cereus, Cereus grandiflorus, when it is dark. Aquatic 

 flowers open and close with the greatest regularity. The white Water Lily 

 closes its flowers at sunset, and sinks below the surface for the night ; in the 

 morning the petals again expand and float on the surface. The Victoria 

 Begia expands for the first time at about six o'clock in the evening and 

 closes in a few hours ; it opens again at about the same time the next 

 morning and remains so until the afternoon, when it closes and sinks 

 below the surface. This sleep of plants is not, of course, confined to their 

 flowers, as leaves open and shut in the same manner ; indeed it is so con- 

 spicuous a phenomenon that it was commented upon as long ago as the 

 time of Pliny. 



Continuous attempts have been made to elucidate the phenomenon of 

 sleep without success. Many theories have been promulgated, but they 

 have fallen short of explaining it. We know that sleep rests the mind more 

 than the body ; or, to put it in another way, the mere mechanical, as apart 

 from the nervous, portion of the organism can be rested without sleep. 

 Negatively, the effect of sleeplessness proves the value and necessity of 

 sleep. Electric light has been used to stimulate the growth of plants, and, 

 coupled with other means of forcing, a continued period of growth secured, 

 thereby obtaining earlier maturity than would have been the case under 

 ordinary circumstances. In most cases plants treated in this way were 

 prevented from sleeping, the result in the case of perennials being to 

 greatly weaken their constitution, the following year's growth being poor 

 and scanty, and in some cases they were scarcely alive. 



The carnivorous plants afford further evidence of the existence of con- 

 sciousness in plants, among which the Venus' Fly-trap {Dionaamuscipula) 



which Linnaeus called the " miracle of nature " — is the most elaborate, and 



is the climax of the order Droseracece. The leaves, about four inches long, 

 consist of a spatulate stalk, which is constricted to the midrib at its junction 

 with the broad blade. The halves of the blade are movable on each other 

 along the.midrib. Round each margin are twenty to thirty long teeth, 

 which interlock in rat-trap fashion with those of the opposite side. The 

 centre of the leaf bears numerous rose-coloured glands, and there are on 

 each half three sensitive hairs. The blades shut up in from eight to ten 

 seconds when one of the sensitive hairs is touched. When an insect 

 alights or a piece of raw meat is placed on the leaf the blades close up, 

 and the rose-coloured glands piur out a fluid which is practically the same 

 as the gastric juice of the animal stomach in its digestive properties. The 

 matter of the insect body or of the meat is thus absorbed into the sub- 

 stance and tissues of the plant, just as the food eaten by an animal is 

 digested. The animal digestion can only be carried on by the brain -force 



