PLANTS WITH TRAPS AXD PITFALLS TO ENSNARE ANIMALS. 



127 



Oregon to Mount Shafta. In both of these the liquid with an acid reaction, which 

 fills the bottom of each utricle, is certainly only secreted by the cells in the interior 

 of the cavity itself, and it is quite impossible that a single drop of the rain or dew 

 deposited upon the plant should reach the interior of the cavity. The hollow 

 petiole is in both plants, above mentioned, utricular or tubular, and only slightly 



Fig. 21.— Ascidia-bearing and Pitcher-plants. 



1 Sarracenia variolam. ^ Darltngtonia Californica. « Sarraceiiia laciniata. 



natural size. 



I Nepenthes viltosa, reduced to one-half 



enlarged towards the top. The dorsal side of each leaf is, however, at its upjier 

 end hollowed out like a cowl or a helmet, and forms a cupola as is shown in 

 fig. 21 - and 21 ^. The orifice or entrance into the utricle is consequently covered 

 over and is reduced to a slit or hole under the hood. The lamina is trans- 

 formed into a lobe, which in Sarracenia variolaris is small and roofs over the 

 orifice of the utricle, and in Darlingtonia is shaped like the tail of a fish, 

 and hangs down in front of the aperture. The lower part of the utricle is of a 

 uniform green colour, but the upper part (i.e. the cupola and lobe-like appendage) 

 has red ribs and veins, and here and there is quite purple. Between the veins the 



