THE ELM, OAK, AND NETTLE 147 
have a close resemblance to a fir cone. As in that case, 
we find big overlapping bracts, with the flowers behind 
them, but the embryo seeds are no longer naked, and the 
seed-vessel would be enough to distinguish it at once, not 
to mention the leaves. It is, of course, these bracts which 
are used in brewing, and their value to the plants lies in 
their action as sails, when the seeds are ripe, and the wind 
comes to carry them far afield. 
The same device of a sail-is used by the Elm, the 
winged seed-vessels of which come down and carpet 
the ground in early spring, before the leaves have dared 
to venture forth; and, on a much smaller scale, by the 
Birch and the Alder. For the present, however, we 
need not go into details about forest trees, for they will 
deserve a supplementary chapter to themselves at the 
end of the book. 
The Spurges are a very widespread, useful, and rather 
uninteresting family. As they are largely responsible for 
the production of India-rubber, or Caoutchouc, though 
some of the figs claim a share in the supply, the cyclist 
and electrician should certainly owe them gratitude, and 
perhaps the fact that they include the Castor Oil plant 
demands our respect, if not our liking; but from the 
point of view of beauty they do not rank high in England. 
The Dog’s Mercury is a good example, and it has the 
merit of being the earliest of our common flowers to 
greet the spring, but its spikes of greenish flowers are 
not very attractive. The Petty Spurge and the Wood 
Spurge, with their red tinge on stem and foliage, are 
more attractive, but their flowers also are not very 
striking. These flowers are borne in spreading groups, 
and the stamens have no envelopes at all, whilst the 
pistils are content with a mere relic of them. Their 
