Flower of the Sun this is Helianthemum, whose Latin name means just that. At the top of the slender woody stem there opens a bright, pale yellow blossom, much like a small yellow single rose. It opens only on a sunny day, and lasts just as long as the sun is in the sky. At sundown the petals drift to the ground and by morning a new bud has reached the point of being ready to open when the sun shines.

Frostweed.

Helianthemum canadense ( L. ) Michx.

Summer Sunny woods.

Frostweed has a reason, also, for its common name. Late in autumn the stiff brown stem, bereft of leaves and its sun-loving flowers, still stands in the winds whipping out of the north. The nights are chill, and frost forms by morning. The thin, ruddy brown bark near the base of the frostweed's stem is cracked, and crystals of frost protrude and sparkle in the sunshine.

Frostweed is never common but is scattered over many parts of the country in dry gravelly hills and sandy slopes. Here the root probes deeply for moisture. The unbranching simple stem rises stiffly into the sunshine, and bears along it pairs of narrow, slightly downy leaves. The frostweeds and rock roses, in the family Cistaceae, are a small group comprising only three genera; Helianthemum, Hudsonia, and Lechea. The latter two are small upright plants with tiny flowers: all three choose sandy places in which to thrust their roots and spread their leaves and flowers.