Page:Popular Science Monthly Volume 63.djvu/260

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256

POPULAR SCIENCE MONTHLY.

Notwithstanding the inroads that are made upon violets they thrive and increase in numbers. One reason for this is that they have hidden underground flowers which do not open, but in which self-pollination is effected and seed produced, giving the violet an extra means of reproducing its kind. The fringed polygala is also provided with these hidden flowers. Many of the so-called weeds, plants which have been accidentally introduced into this country, are so well fitted for the struggle for existence that they have successfully combated against unnatural environment and have increased enormously in numbers and geographical distribution. Many of these, as the daisy (white weed), chickory, dandelion and the thistle, as well as the native golden rods and asters, are members of the compositæ family. This group is represented by over 10,000 species, comprising one tenth of all the seed plants, each represented by many individuals of a wide range. This family of plants is the most highly differentiated. Numbers of small flowers are arranged in compact heads or clusters, presenting a complete organization in which there is a division of labor among the members of a head. They present various contrivances for cross-pollination and various adaptations of the calyx into agents for seed dissemination.

In the early summer the fields are white with daisies, which later are replaced by the golden rods. Their

Midas touch hath turned the hind to gold
For us to have and hold.

Quantities of golden rod, as well as daisies, asters, golden-ragwort, chicory, fleabane and rudbeckia can be gathered without causing any serious reduction in their numbers. The desire to possess armfuls of flowers is thereby gratified, as is also the farmer who counts these plants as pests.