Hellianthemum canadense (name means "sunflower," so called because the flowers open only in sunshine). - Family, Rockrose. Color, yellow. Sepals, 5, 2 of them long, thin, bract-like, hairy or whitish and downy. Petals, 5, sometimes none. Stamens, 3 to 10, or numerous. Pistil, 1, with a 3-lobed, sessile stigma. Stem, very hoary, at first simple, then branched. Leaves, alternate above, opposite below, simple, numerous, lance-shaped to oblong, hoary underneath. Large petal-bearing flowers, bloom June to August.
This singular plant produces two kinds of blossoms, the earlier in July, a large, 5-petaled flower, opening only in sunshine, dropping its petals the next day, 1 inch across, with many stamens lying flat against the petals. The pod is 1-celled, with numerous seeds. The blossom, resembling an evening primrose, is solitary on the stem. Later in the season - August and September - much smaller flowers cluster in the axils of the leaves up and down the stem, with or without petals, with 3 to 10 stamens and very small, roundish, few-seeded pods, giving the plant an entirely different appearance.
The plant gets its name from the curious ice-crystals which form on the stem near the root in November on frosty mornings.
Mr. Gibson says of this frost flower (Sharp Eyes): "It is a flower of ice-crystal of purest white, which shoots from the stem, bursting the bark asunder, and fashioned into all sorts of whimsical, feathery curls and flanges and ridges. It (the crystal) is often quite small, but sometimes attains three inches in height and an inch or more in width. It is said to be a crystallization of the sap of the plant, but the size of the crystal is often out of all proportion to the possible amount of sap within the stem, and suggests the possibility that the stem may draw extra moisture from the soil for this especial occasion." In sandy soil, Maine to Minnesota and southward.