68 ARRANGEMENT OF FLORAL LEAVES 



carpels alternate with the inner whorl of stamens, so that they 

 are opposite to the petals in place of being opposite to the 

 sepals (fig. 1 66). Such flowers are said to ht obdiplostemonous 

 {e.g. Geranium, Oxalis). 



(ii.) Unequal Growth. — In many flowers the floral leaves 

 which form a single whorl are not all alike in size and shape. 



Fig. g6. — Vertical section of flower of Garden Pea. Fig. 97. — Separated petals of ditto. 



The flower as a whole, or the whorl itself, is then said to be 

 irregular. The corollas of the Pansy, Pea (figs. 96, 97), and 

 Dead Nettle are irregular. In the Dead Nettle (fig. 191) two 

 stamens with short, and two with long, filaments form one 

 whorl. On the other hand, the androecium of the Wallflower 

 (fig. 88) consists of two stamens with .shorter, and four with 

 longer, filaments ; but the two short stamens form one whorl, 

 and the four long ones comprise another, so that the androecium 

 is not irregular. When all the floral leaves of each separate 



