96 TYPES OF BRITISH PLANTS 
In a complete flower we shall find at most five different 
types of modified leaves, arranged in circles around a 
common centre. This centre is formed by the branch 
upon which the modified leaves are borne, 7.e. the flower 
stalk, and the leaves are not distributed over the branch 
like the foliage leaves, but generally crowded together at 
the top of it. The names of the five sets of modified 
leaves are the bracts, the calyx, the corolla, the stamens, 
and the pistil or carpels.* Upon these last two devolve 
the essential duties of the flower in producing seed, and 
unless one or other is present, the flower has no direct 
use from that point of view. It may be attractive and 
ornamental, as are garden roses, but for continuing the 
species it is of no effect in itself, although, as we shall 
see later, such flowers may help indirectly. Similarly, 
the outer circles, the bracts, the calyx, and the corolla, 
can do nothing by themselves, but as guardians of the 
essential organs, as attracters of the insects which may 
help them to do their work, they are invaluable. 
Let us now examine these five individually, begin- 
ning with the outside ring, and working in towards 
the centre. 
The bracts are the least modified of the leaf structures 
as a rule, and do a good deal of the ordinary leaf work 
with their chlorophyll machinery. They appear at 
various places on the leaf stalk, and are generally close 
beneath the calyx, and quite inconspicuous. In some 
cases, however, they play a prominent part. The ordinary 
Arum of the hedgerows, which you must know either 
under that name or as Lords-and-Ladies, or as Cuckoo 
* Bract means a thin plate ; calyx, a husk, cup, or covering ; corolla, 
a little crown, or wreath ; stamen, a thread, or fibre ; pistid is another 
form of pestle; carpel, a little fruit. 
