(Helianthemum Canadense) Rock-rose family
FlowersSolitary, or rarely 2; about 1 in. across, 5-parted, with showy yellow petals ; the 5 unequal sepals hairy. Also abundant small flowers lacking petals, produced from the axils later. Stem: Erect, 3 in. to 2 ft. high; at first simple, later with elongated branches. Leaves: Alternate, oblong, almost seated on stem.
Preferred HabitatDry fields, sandy or rocky soil.
Flowering SeasonPetal-bearing flowers, MayJuly. DistributionNew England to the Carolinas, westward to Wisconsin and Kentucky.
Only for a day, and that must be a bright sunny one, does the solitary frost-flower expand its delicate yellow petals. On the next, after pollen has been brought to it by insect messengers and its own carried away, the now useless petal advertisements fall, and the numerous stamens, inserted upon the receptacle with them, also drop off, leaving the club-shaped pistil to develop with the ovary into a rounded, ovoid, three-valved capsule. Notice how flat the stamens lie upon the petals to keep safely out of reach of the stigma. Another flower, exactly like the first, now expands, and the bloom continues for weeks. Why does only one blossom open at a time ? Because the whole aim of the showy flowers is to set cross-fertilized seed, and when only one at a time appears, pollination not only between distinct blossoms but between distinct plants insures the healthiest, most vigorous offspringa wise precaution against degeneracy, in view of the quantities of self-fertilized seed that will be set late in summer by the tiny apetalous flowers that never open (see p. 108). Surely two kinds of blossoms should be enough for any species; but why call this the frost-flower when its bloom is ended by autumn ? Only the witch-hazel may be said to flower for the first time after frost. When the stubble in the dry fields is white some cold November morning, comparatively few notice the ice crystals, like specks of glistening quartz, at the base of the stems of this plant. The similar Hoary Frost-weed (H. majus), whose showy flowers appear in clusters at the hoary stem’s summit, in June and July, also bears them. Often this ice formation assumes exquisite feathery, whimsical forms, bursting the bark asunder where an astonishing quantity of sap gushes forth and freezes. Indeed, so much sap sometimes goes to the making of this crystal flower, that it would seem as if an extra reservoir in the soil must pump some up to supply it with its large fantastic corolla.