Order 13. CISTÀCEÆ. (Rock-rose Family.)
Low shrubs or herbs, with regular flowers, distinct and hypogynous mostly indefinite stamens, a persistent calyx, a 1-celled 3–5-valved capsule with as many parietal placentæ borne on the middle of the valves, and orthotropous albuminous seeds.—Sepals 5; the two external much smaller, bract-like, or sometimes wanting; the three others a little twisted in the bud. Petals 3 or 5, convolute in the opposite direction from the calyx in the bud. Anthers short, innate, on slender filaments. Style single or none. Ovules few or many, on slender stalks, with the orifice at the apex. Embryo long and slender, straightish or curved, in mealy albumen; cotyledons narrow.—Leaves simple and mostly entire, the lower usually opposite, and the upper alternate. Inert plants.
1. Helianthemum. Petals 5, crumpled in the bud, fugacious (or none). Stigma nearly sessile. Stamens and ovules numerous in the petal-bearing flowers.
2. Hudsonia. Petals 5, fugacious. Stamens 9–30. Style long and slender. Pod strictly 1-celled, 2–6-seeded. Heath-like.
3. Lechea. Petals 3, persistent. Stamens 3–12. Style none. Pod partly 3-celled, the imperfect partitions bearing broad 2-seeded placentæ.
1. HELIÁNTHEMUM, Tourn. Rock-rose.
Petals 5, crumpled in the bud, fugacious. Styles short or none in our species; stigma 3-lobed. Capsule strictly 1-celled. Embryo curved in the form of a hook or ring.—Flowers in most N. American species of two sorts, viz., primary or earlier ones, with large petals, indefinitely numerous stamens and many-seeded pods; and secondary, or later ones, which are much smaller and in clusters, with small petals or none, 3–10 stamens, and much smaller 3–few-seeded pods. The yellow flowers open only once, in sunshine, and cast their petals by the next day. (Name from ἥλιος, the sun, and ἄνθεμον, flower.)
1. H. Canadénse, Michx. (Frost-weed.) Petal-bearing flowers solitary; the small secondary flowers clustered in the axils of the leaves, nearly sessile; calyx of the large flowers hairy-pubescent, of the small ones hoary, like the stem and lower side of the lanceolate-oblong leaves.—Sandy or gravelly dry soil, Maine to Minn. and southward. June–Aug.—Stems at first simple. Corolla of the large flowers 1´ wide, producing pods 3´´ long; pods of the smaller flowers not larger than a pin's head. A variety is more hoary, and with a stronger tendency to multiply the minute clustered flowers. Late in autumn crystals of ice shoot from the cracked bark at the root, whence the popular name.
2. H. corymbòsum, Michx. Flowers all clustered at the summit of the stem or branches, the petal-bearing ones at length on slender stalks; calyx woolly.—Pine barrens, N. J. and southward along the coast.
2. HUDSÒNIA, L.