174 STRUCTURAL BOTANY 



that it is an excellent type of the flowers of Monocoty- 

 ledons generally, most of which are built on the same 

 ground-plan. 



We already know the external characters of the 

 flower ; we will now shortly trace its development. 



a. Development of the Flower 



The flower-bud arises, like any other branch of the 

 stem, from the external layers of tissue of the growing- 

 point, with which it is directly continuous. It is formed 

 in the axil of a bract, and in some species, as in that 

 figured, the axis of the flower itself produces a small 

 lateral vegetative leaf, termed a bracteole (see Fig. 71, 

 B, b). In the White Lily, however, the latter is absent. 

 The future flower has at first a broadly rounded shape. 

 The earliest stage shown in the figures is that just after 

 the sepals have appeared. All the three sepals do not 

 arise at the same time, but one after the other (see 

 Figs. 71 and 72, s). Next, the three petals appear, 

 all at the same time, and exactly between the sepals 

 (see Fig. 73,^). After this, three fresh outgrowths 

 show themselves just inside the petals, and alternating 

 with them, so that they lie exactly opposite the sepals ; 

 these are the three outer stamens (st a , Fig. 74). Very 

 soon afterwards the three inner stamens appear (st, Fig. 

 75) exactly between the first three, and therefore 

 opposite the petals. Lastly, around the centre of the 

 growing point, yet three other structures arise, each 

 shaped like a horseshoe, open towards the inside of 

 the flower. These are the young carpels, forming the 

 pistil, which is the innermost whorl of the flower 



