228 



ORGANOGRAPHY. 



expansions is very evident. If the calyx has one or more 

 tubular prolongations downwards, it is said to be calcaraie or 

 spurred. Only one spur may be present, as in the Indian Cress 

 ( Tropceohim) (Jig. 454), where the spur is formed by three sepals, 



Fig. 454. 



Fig. 456. 



Fia. 4.54. Flower of the Indian Ciees c. Spurred calyx Fig. 455. Flower of 



Columbine {Aquileyia rw/yaris) with all the sepals spurred. 



or in the Larkspur, wliere it is formed by one ; or each of the 

 sepals maybe spurred, as in the Columbine (Aquilegia) (Jig. 455). 

 In the Pelargonium, the spur instead of being free from the 

 pedicel, as in the above instances, is united to it. 



On the outside of the calyx of some 

 flowers, as in those of many Malvaceous 

 plants (Jig. 456), and also in those of 

 the Pink (Jig. 460) and Hose tribes (Jig. 

 441), tliere is placed a whorl of leaf-like 

 organs which are considered by some 

 botanists as an outer calyx, to which the 

 names of cali/culus and epi- calyx have 

 been given, but these are evidently of tlie 

 same nature as the involucre already 

 noticed (see page 189). The external 

 covering of each of the flowers and fruits 

 (Jig. 453) of the Scabious, furnisli us an- 

 other example of this calyciform invo- 

 lucre. 



The duration of the calyx varies in 

 different flowers. Thus it is caducous 

 or fugacious, wlicn it falls off as the flower expands, as in 

 the Poppy {fig. 457). In the Eschscholtzin the caducou.s 

 caly.K separates from the hollow thalamus to which it is articu- 



Fio- 4.'',6. Calyx 



biscus surroundeil by 

 an epi-calyx or invo- 

 lucre. 



