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.
Flowers - Very small, white, distant, growing on numerous scapes 1 to 5 in high; in formation each flower is similar to all the mustards, except that the 4 petals are 2-cleft, destroying the cross-like effect. Leaves: 1/2 to 1 in. long, in a tuft or rosette on the ground, oblong or spatulate, covered with stiff hairs.
Preferred Habitat - Waste lands, sandy fields, and roadsides.
Flowering Season - February - May.
Distribution - Throughout our area; naturalized from Europe and Asia.
An insignificantly small plant, too common, however, to be wholly ignored. Although each tiny flower secretes four drops of nectar between the bases of the short stamens and the long ones next them, it would be unreasonable to depend wholly upon insects to carry pollen, since there is so little else to attract them. Therefore the anthers of the four long stamens regularly shed directly upon the stigma below them, leaving to the few visitors, the small bees chiefly, the transferring from flower to flower of pollen from the two short stamens which must be touched if they would reach the nectar. In spite of the persistency with which these little blossoms fertilize themselves, they certainly increase at a prodigious rate; but how much larger and more beautiful might they not be if they possessed more executive ability!
A similar but larger plant, with its hairy leaves not only tufted at the base, but also alternating up the stiff stem, is the Hairy Rock-cress (Arabis hirsuta), whose white or greenish flowers, growing in racemes after the usual mustard fashion, are quickly followed by very narrow, flattened pods two inches long or less. Around the world this small traveller has likewise found its way, choosing rocky places to display its insignificant flowers throughout the entire summer to such small bees and flies as seek the nectar in its two tiny glands. It is not to be confused with the saxifrage or stone-breaker.