PARTS OF THE FLOWER 345 



The flowers of some kinds of seed plants are of two 

 kinds, the one producing microsporangia alone (" male " 

 flowers), the other megasporangia alone ("female" 

 flowers) ; but most seed plants have flowers producing 

 both kinds of sporangia, though on separate floral leaves, 

 and these are called " hermaphrodite " flowers. 



Parts of the Flower. — The flower is a condensed 

 shoot in which the internodes have elongated very little, if 

 at all, and the crowded nodes on which the floral leaves 

 are borne are together called the receptacle (Fig. 57). 

 The lower part of the same axis continuous with the 

 receptacle is often bare of leaves, and is called the 

 peduncle if the flowers are borne singly arising from 

 vegetative shoots, the pedicel if it belongs to a system 

 of branches {inflorescence), each bearing a flower. Leaves 

 in the axils of which flowers are borne or themselves 

 borne on peduncle or pedicel and somewhat different 

 from the foliage leaves are called bracts. 



Perianth. — ^The floral leaves themselves are arranged 

 in whorls (a whorl is a circle of leaves arising at the 

 same level on the axis) one above the other. The 

 outer (lowest) leaves form the perianth, which very 

 commonly consists of two whorls, the calyx, whose 

 leaves, the sepals, are often green and rather like small 

 simple foliage leaves, and the corolla, whose leaves, the 

 petals, are generally larger and more or less brightly 

 coloured. Sometimes, however, the perianth consists 

 of one whorl only, or of two whorls whose leaves are 

 alike. In the flower bud the perianth leaves are curved 

 inwards, enclosing the two inner (upper) whorls of 

 floral leaves which bear the two kinds of sporangia. 



Stamens and Carpels. — The first (lower) of these is 

 called the andrcecium,^ the individual leaves the stamens. 



I Greek avrip, dvdpdg (aner, andros), a man, because the male gametes 

 are formed in the microspores produced by the stamens. 



