THE ANGIOSPERMAE ii 



5/ 



giving point to Burkill's comparison of zygomorphic flowers to sectorial 

 chimaeras, plants in which tissues of different genetic character as well as 

 different growth characters are united sectorially in a single shoot. 



Fig. 1 129. — Aquilegia vulgaris, flower with spurred 



petals. 



The calyx has a biological importance of its own, quite apart from the 

 corolla. Its general function of protection for the inner parts during the 

 bud stage is often supplemented by other specialized functions in this and 

 also in other respects. One of the most important of these additional 

 functions is the protection of the developing fruit, after anthesis. An 

 example of this is H\oscyamiis (Henbane), where the base of the synsepalous 

 calyx develops into a hard, rounded case, enclosing the fruit and surmounted 

 by a crown formed of the free points of the sepals. A very striking example 

 is afforded by Physalis peruviana (Cape Gooseberry) in which the berry is 

 enclosed in a large, inflated case (Fig. 1 130), composed of the bright orange- 

 coloured and almost petaloid calyx. Such persistent calyces may also 

 become agents of dispersal, but these we shall deal with later (see 

 p. 1556). At the opposite extreme are the caducous calyces which, having 

 no function beyond the initial one of protecting the bud, are dropped off 

 when the flower opens, as in Papaver. 



The calyx may often supplement or replace the corolla as a means of 

 advertising the flower, of which there are numerous examples in the 

 Ranunculaceae, e.g., Caltha, Helleboriis, Clematis, etc. The garden /fv^''««- 

 gea is also an example known to everyone. Instances of such modifications 

 of the sepals are extremely numerous and the change of character is not 

 always as simple as in the cases cited. It is notable that not infrequently 

 the protective function, which is no longer carried out by the modified 



