100 TYPES OF BRITISH PLANTS 
they may be of indirect use, either as protections, or 
as guides to visiting insects. In double flowers, the 
stamens are modified into petals, the leaf-like character 
of which is still more easily recognised. 
We have now to consider what are the chief duties 
of stamens. You may remember that we found amongst 
mosses and the prothallia of ferns certain groups of cells 
which we then called antheridia. You may also re- 
member that these split up into antherozoids, 7.c. little 
pieces of free protoplasm without any cell-wall, that 
swam about in the moisture of the plant until they found 
one of the flask-shaped archegonia ready to be fertilised, 
and that then they forced their way down its neck. 
Now the anthers, as their name suggests, have a similar 
part to play. The disadvantage of the process in the 
lower plants was that fertilisation could only be secured 
where there was enough water for these little anther- 
ozoids to swim in, and the result is seen in the rather 
limited distribution of both ferns and mosses. Now the 
flowering plants have got rid of this handicap, The 
anthers of the stamens, with which they are all provided, 
produce a crowd of pollen-grains (meaning fine flour), 
known collectively as pollen. The contents of the cells 
are no longer free, but are provided with a wall. The 
usual colour, as you may see for yourselves on almost any 
plant, is a golden, or orange, yellow. These grains are 
built up inside the anthers, which split when fully ripe 
and let the fertilising grains slip out to perform their 
part of the task of constructing the seed. 
Before we consider how this has to be accomplished, 
let us go on and examine the other half of the duplicate 
machinery, namely, the pistils or carpels. As with all 
the other sets of organs that surround the plant, the 
