io6 UTRICULARIA [CH. 



record, it may be noted that an inflorescence-bract sometimes 

 develops into a water-leaf or even an entire water-shoot, while 

 a bladder rudiment may develop into a water-shoot 1 . In the 

 development of the seedling, the primary leaves may be re- 

 placed by stolons 2 . 



The apical development of the Bladderworts gives little help 

 in interpreting their morphology. In Utricularia vulgaris (Fig. 

 72), for example, the apex of the shoot is coiled up in a singular 



FIG. 72. Utricularia vulgaris, L. A, spirally coiled end of a shoot, of which a is 

 the apex ; s i -s 5 , young shoots ; /', youngest leaves ; I, older leaves (between / and /' 

 some leaves have been removed) ; h, hairs (mucilage glands) ; i, young inflorescence 

 growing from the base of s 5 . B, developing bladder; a, curved apex of shoot; 

 SL first shoot, and /, single leaf or two leaves fused; a, s x and / fuse to form 

 bladder ; s 2 is second shoot which may give rise to a branch or a secondary bladder. 

 [Adapted from Pringsheim, N. (1869).] 



way which recalls a young fern frond. The " leaves " (/) arise 

 in two lateral rows, and there is a third row of rudiments (^ J 5 ) 

 on the concave face, which give rise to air-shoots. The develop- 

 ing bladders on a leaf are indicated in Fig. 73, while Fig. 72 B 

 illustrates that view of the composite origin of the single 

 bladder which regards it as derived from both axial and foliar 

 elements 3 . 



In general, the only safe conclusion to be drawn from a study 



1 Gluck, H. (1906). 2 Goebel, K. (1891). 



3 Pringsheim, N. (1869). 



