This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flower - Variable, scarlet, deep salmon, copper red, flesh colored, or rarely white; usually darker in the centre; about 1/4 in. across; wheel-shaped; 5-parted; solitary, on thread-like peduncles from the leaf-axils. Stem: Delicate; 4-sided, 4 to 12 in. long, much branched, the sprays weak and long. Leaves: Oval, opposite, sessile, black dotted beneath.
Preferred Habitat - Waste places, dry fields and roadsides, sandy soil.
Flowering Season - May - August.
Distribution - Newfoundland to Florida, westward to Minnesota and Mexico.
Tiny pimpernel flowers of a reddish copper or terra cotta color have only to be seen to be named, for no other blossoms on our continent are of the same peculiar shade. Thrifty patches of the delicate little annuals have spread themselves around the civilized globe; dying down every autumn, and depending on seeds alone to keep the foothold once gained here, in Mexico and South America, Europe, Egypt, Abyssinia, Cape of Good Hope, Mauritius, New Holland, Nepaul, Persia, and China. What amazing travellers plants are! The blue-flowered plants are now believed to be a distinct species (A. coeruled).
Notwithstanding the fact that many birds delight to feast on the seeds, or perhaps because of it, for many must be dropped undigested, the scarlet pimpernel is one of the most widely distributed species known.
Before a storm, when the sun goes under a cloud, or on a dull day, each little weather prophet closes. A score of pretty folk names given it in every land it adopts testifies to its sensitiveness as a barometer. Under bright skies the flower may be said to open out flat at about nine in the morning and to begin to close at three in the afternoon. No nectar is secreted unless there may be some in the colored hairs which clothe the filaments. As if it knew perfectly well that however desirable insect visitors are - and it has an excellent device for compelling them to transfer pollen - it is likewise independent of them, it takes no risk in exposing the precious vitalizing dust to wind and rain, but closes uptight, thereby bringing its pollen-laden stamens in contact with its stigma. Manifestly, it is better for a plant having aspirations to colonize the globe to set even self-fertilized seed than none at all.