Chapter XIII 



221 



Utricularia, Bioviilaria 



size and shape of these floats are characteristic of different species 

 possessing them. In U. stellaris they are short and of relatively 

 wide diameter. In U. injlata they are long (4-5 cm.) and clavate. 



Fig. 6. — 1-7, Utricularia purpurea. — i, Early stages of germination of a seed {2>-2> 

 mm long) from which only one growing point arose (to be followed by others later in all 

 probability); 2, Three figures in a row, three views of an early stage of germination, a 

 later stage of which is shown in 3, in which two young growing points show circination; 

 4 and 5, Two following stages in the germination of a seed which produced three growing 

 pomts all of nearly the same age, with a fourth, secondary to the middle growing point; 

 6, A case in which fasciation occurred, the two figures on the right show an early stage 

 of germination, a much later stage is shown on the left, in which it is seen that one of the 

 growing points had divided, an abnormality; 7, An advanced stage in germination (15 mm 

 long), one of the three growing points still quiescent; five whorls of branches (the maximum 

 seen) were produced, as shown on the longer stolon of this figure. At the first whorl of this, 

 the bud of a branch stolon of indefinite growth is seen. No traps are produced on the two 

 dorsal branches of the third and fourth whorls. 



8-10, Utricularia cleistogama. — 8, Early stage of germination showing primary stolon 

 and primary leaf, with the primary trap on the leaf near its base; 9, A later stage in detail 

 showing the origin of the trap from the leaf base; 10, A more advanced stage of the seed- 

 ling in which a second leaf arose in the place of a primary trap. 



Still another form of leaf occurs on short stolons at the base of 

 the scape of the inflorescence (Buchenau 1865), the so-called rhi- 

 zoids, several of which are usually present. Their leaves are much 

 reduced in size and have very small pinnae which are curved and 

 crowded into claw-Hke masses. More or less of each pinna is densely 

 covered with mucilage glands quite like those scattered over the 

 whole plant surface {U. vulgaris, etc.). 



