io8 UTRICULARIA [CH. 



The submerged and aerial parts of the axis differ, in fact, so 

 conspicuously in their internal structure that van Tieghem 1 

 suggested that, if they were submitted separately to an anato- 

 mist, he would probably attribute them to distinct and un- 

 related plants! 



The leaf of Utricularia minor is typically that of a submerged 

 plant (Fig. 74) 2 . The bundle is extremely small, consisting 

 generally of a single annular tracheid surrounded by thin- 

 walled, elongated elements. The air spaces in the mesophyll 

 reach to the epidermis, which contains the greater part of the 

 chlorophyll, and is the most conspicuous region of the leaf. 



FIG. 74. Utricularia minor, L. T.S. lower part of leaf. (xi75.) 

 [Schenck, H. (1886).] 



It seems thoroughly in keeping with the uncannily abnormal 

 morphology and the exceptional carnivorous habits of the 

 Utricularias, that they should sometimes locate themselves in 

 odd situations. The oft-quoted case of those Bladderworts which 

 live in association with certain South American Bromeliads, is 

 an instance in point. The leaf rosettes of some Tillandsias form 

 vase-like cavities, which collect and retain water. Utricularia 

 nelumbifolia has been described by a traveller in Brazil 3 as only 

 to be found growing in the water which collects in the bottom 

 of the leaves of a large Tillandsia occurring on an arid, rocky 

 part of the Organ Mountains, at about 5000 feet above the sea. 



1 Tieghem, P. van (1868). 2 Schenck, H. (1886). 



3 Gardner, G. (1846). 



