84 | ELEMENTARY BOTANY 
CHAPTER VI 
THE FLOWER 
AFlower, 1 the flower of a buttercup is examined, it will be 
a Modified seen to consist of four sets of leaves, arranged on 
Shoot. a central stem ; this stem is the apex of the flower 
stalk, and is called the receptacle. The leaf, in the axil of 
| which the flower stalk 
s situated, is a bract; 
t is not always pre- 
ent. <A flower is thus 
modified shoot, differ- 
ng from the ordinary — 
oliage shoot already 
described as having : 
1, Very short inter- 


3 2. No buds in the axils. 
Fic. 34.—Vertican Section or Burrercup, 8+ Leaves — frequently 
re, receptacle ; s, sepals; p, petals; a, whorled and specially 
stamens ; ¢, carpels, modified for the produc- 
A oak tion of seed. 
Floral The outermost leaves of the flower are called 
Leaves. sepals, and together form the calyx or cup, in 
which the rest of the flower is, as it were, contained. This is 
best seen in the bud where, as in poppy, the calyx forms a 
complete covering for the other floral leaves and, as soon as 
the flower opens, drops off. | 
The next leaves are the petals, forming the corolla. The 
calyx and corolla are not essential for the development of 
fruit and seed, and are often absent, especially in the flowers 
of trees. | 
The essential leaves of a flower are: (1) the stamens, the 
third whorl of leaves, and (2) the carpels, the innermost leaves, 
