i6o Transactions of the [Sess. 



lid is either erect, or thrown back so as to direct all the rain that 

 falls upon it into the pitcher ; and in the second, of which S. variolaris 

 may be taken as tlie type, the lid is thrown somewhat forward, so as 

 to prevent the rain from entering. The pitchers generally contain 

 water, and it was supposed by Catesby that these receptacles served 

 as a secure retreat for insects from Frogs and other animals which feed 

 upon them ; and by Linnfeus and others, that they served as water- 

 reservoirs for birds and other animals, especially in dry weather. 

 This idea probablj^ originated from the fact that some birds slit open 

 the pitchers with their beaks ; but the probability is that these birds 

 slit open the pitchers to get at the larvcB of insects which have 

 dropped their eggs amongst the mass of decaying organic matter, where 

 they would get suitable nourishment. 



It was Linnteus who first made the suggestion, which has since 

 been worked out in detail by Baillon, that the pitchers of Sarracenia 

 are analogous to the leaves of Water-lilies ; and he supposed that 

 they were originally aquatic in their habits, and had ISTymphsea-like 

 leaves, but that they afterwards took to terrestrial habits, and their 

 leaves became hollowed out to contain the Avater in which they could 

 not float. The pitcher-lid would thus represent the apex of the leaf. 

 The internal structure of the pitchers is exceedingly beautiful, and in 

 most species presents, like Nepenthes, three distinct surfaces. The 

 first is the " attractive " surface, which occupies the inner part of the 

 lid and the mouth of the pitcher. The lid is often more highly 

 coloured than the rest of the pitcher, and, in common with the mouth, 

 is studded over with honey-secreting glands. These glands are also 

 found on the outside of the pitcher. The epidermis cells of the inner 

 surface of the lid are wavy in outline, and many of them are pro- 

 longed on their free surface into sharp downward-directed hairs. 

 Occupying the upper part of the inner surface of the pitcher proper, 

 and extending some distance down its cavity, is the " conducting " 

 surface. In this each epidermis cell is prolonged downwards into a 

 short, glassy, sharp-pointed hair, which is finely striated. These hairs 

 overlap like the tiles of a house, and they thus afford no foothold to 

 insects. The whole of the cavity of the pitcher below the conduct- 

 ing surface is occupied by the " detentive " surface. In this many 

 of the epidermis cells are prolonged into enormously elongated down- 

 ward-directed hairs, which increase in length towards the bottom of 

 the pitcher ; and as the cavity diminishes in width, they meet in the 

 centre, and thus completely prevent the escape of any insect which 

 may have been lured into it. Secreting glands are embedded in the 

 detentive surface of all the species with the exception of S. purpurea. 

 In this species, however, there is a special glandular sui-face which oc- 

 cupies a portion of the wall of the pitcher between the conducting and 

 detentive surfaces. The epidermis cells of this surface are wavy in 

 outline, and embedded amongst them are numerous secreting glands. 



