Rockrose Family (Cistaceæ)
(A) Frostweed: Rockrose (Helianthemum canadense). This little perennial is very remarkable and unique, because late in autumn crystals of ice form about the cracked bark of the root. It is also remarkable for the fact that it has two sets of flowers, the first ones in June and later ones in July or August.
The leaves are small, oblong-lanceolate, hoary with white hairs on the underside, alternating along the stem that rises from 10 to 18 inches high. Both the early and late flowers are fertile. Frostweed grows in sandy, dry soil from Me. to Minn. and southward.
(B) Hudsonia (Hudsonia tomentosa) is a low-branching, little shrub rising only 5 or 10 inches above ground. Its branching stems are closely crowded with tiny, scale-like oval leaves about one half inch long.
The small yellow flowers that are crowded along the ends of the branches open only in sunshine; the five tiny yellow petals surround numerous stamens and a long, slender style. Hudsonia is found on sandy shores from N. B. to Va., and along the Great Lakes.