May, and a
heavy rainstorm has caused the petals of a trillium to forget
themselves and return to their primitive hue of leafy green. A month
later we come upon a buttercup, one of whose sepals has grown out as a
small but perfect leaf. Later still in summer we find a rose in the same
surprising case, while not far off is a columbine bearing pollen on its
spurs instead of its anthers. What family tie is betrayed in all this?
No other than that sepals, petals, anthers and pistils are but leaves in
disguise, and that we have detected nature returning to the form from
which ages ago she began to transmute the parts of flowers in all their
teeming diversity. The leaf is the parent not only of all these but of
delicate tendrils, which save a vine the cost of building a stem stout
enough to lift it to open air and sunshine. However thoroughly, or
however long, a habit may be impressed upon a part of a plant, it may on
occasion relapse into a habit older still, resume a shape all but
forgotten, and thus tell a story of its past that otherwise might remain
forever unsuspected. Thus it is with the somewhat rare "sport" that
gives us a morning glory or a harebell in its primitive form of unjoined
petals. The bell form of these and similar flowers has established
itself by being much more effective than the original shape in dusting
insect servitors with pollen. Not only the forms of flowers but their
massing has been determined by insect preferences; a wide profusion of
blossoms grow in spikes, umbels, racemes and other clusters, all
economizing the time of winged allies, and attracting their attention
from afar as scattered blossoms would fail to do. Besides this massing,
we have union more intimate still as in the dandelion, the sun-flower
and the marigold. These and their fellow composites each seem an
individual; a penknife discloses each of them to be an aggregate of
blossoms. So gainful has this kind of co-operation proved that
composites are now dominant among plants in every quarter of the globe.
As to how composites grew before they learned that union is strength, a
hint is dropped in the "sport" of the daisy known as "the hen and
chickens," where perhaps as many as a dozen florets, each on a stalk of
its own, ray out from a mother flower.

While for the most part insects have been mere choosers from among
various styles of architecture set before them by plants, they have
sometimes risen to the dignity of builders on t