THE FLOWER 



79 



arranged in whorls. Such a similarity between the 

 arrangement of floral leaves on the thalamus and of 

 foliage leaves on a shoot further bears out the homo- 

 logy of flowers with shoots. When the floral leaves, 

 especially the sepals or petals, or both, are arranged 

 spirally, the flower is said to be acyclic ; when they 

 are arranged in whorls, the flower is said to be 

 CYCLIC. The majority of flowers are cyclic, and only 

 a small minority are acyclic. 



Further, when the leaves on a shoot are in whorls, 

 they are usually found to decussate. A similar de- 

 cussation is met with in floral whorls. For instance, 

 in ata and kantali-champa the calyx is the lower- 

 most whorl of three sepals, and next above are two 

 whorls of corolla of three petals each, the outermost 

 whorl decussating with the calyx and the innermost 

 whorl decussating with the outermost whorl of corolla. 

 This is another evidence in support of the foliar 

 nature of the whorls of flowers. This decussation of 

 the whorls of flowers is known as alternation. 



Ordinarily the sepals are green and the petals 

 coloured, but, whether green or coloured, they have 

 usually the structure and form of leaves, so that their 

 foliar nature is quite obvious. It is only when we 

 come to consider the stamens and carpels that their 

 foliar nature becomes difficult to make out. In the 

 case of stamens the difficulty vanishes if we examine 

 first their parts, secondly, such flowers as shalook 

 and padma, and, thirdly, what is known in gardening 

 as the doubling of flowers. For example, a stamen 

 ordinarily consists of a thin stalk surmounted by a 

 comparatively broad portion, the latter divided in the 

 middle by a middle line. The stalk corresponds to 

 the petiole, the broad portion to the blade, and the 

 middle line to the mid-rib of a leaf. In shalook and 



