BLUE and PURPLE ASTERS or STARWORTS
Thistle family
Evolution teaches us that thistles, daisies, sunflowers, asters,
and all the triumphant horde of composites were once very
different flowers from what we see today. Through ages of natural
selection of the fittest among their ancestral types, having
finally arrived at the most successful adaptation of their
various parts to their surroundings in the whole floral kingdom,
they are now overrunning the earth. Doubtless the aster's remote
ancestors were simple green leaves around the vital organs, and
depended upon the wind, as the grasses do - a most extravagant
method - to transfer their pollen. Then some rudimentary flower
changed its outer row of stamens into petals, which gradually
took on color to attract insects and insure a more economical
method of transfer. Gardeners today take advantage of a blossom's
natural tendency to change stamens into petals when they wish to
produce double flowers. As flowers and insects developed side by
side, and there came to be a better and better understanding
between them of each other's requirements, mutual adaptation
followed.
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