This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Woody herbs or low shrubs, more or less branching, with showy yellow flowers, and with other much smaller apetalous cleistogamous ones. Petals in the larger flowers large, fugacious, the stamens numerous. Placentae or false septa 3. Ovules 2 on each placenta; style short; stigma capitate or 3-lobed; capsule I-celled; seeds with long funicles; embryo curved. [Greek, golden flower.]
About 20 species, natives of North and Central America, a few in South America. Besides the following, about 8 others occur in the Southern States. Type species: Crocanthemnm carolinianum (L.) Spach. Some of the species are known as Rock-rose or Sun-rose. The genus has been included by authors in the Old World genera Helianthemum L., and Halimium Spach.
Petaliferous flowers solitary, few or several; apetalous flowers in axillary sessile clusters.
Petaliferous flowers 5-12, in a short terminal cymose raceme, their capsules 1 1/2" - 2" long. little, if at all, overtopped by the short later axillary branches; capsules of the apetalous flowers
about 1" in diameter.
Petaliferous flowers solitary, rarely 2, their capsules 3"-4" long, much overtopped by the later elongated axillary branches; capsules of the apetalous flowers nearly 2" in diameter.
Flowers all cymose at the summit of the stem, the petaliferous ones slender-pedicelled.
Lechea major L. Sp. Pl. 90. 1753.
Helianthemum majus B.S.P. Prel. Cat. N. Y. 6. 1888.
Halimium majus Grasser, Pflanzenreich 14: 50. 1903.
Hoary-canescent, stems erect, 1°-2° high, at first simple, later with numerous short ascending branches. Leaves oblong-lanceolate or oblanceolate, acute or obtuse, 8"-18" long, stellate-canescent beneath, darker above, short-petioled; petaliferous flowers 5-12 in a terminal cymose raceme, their corollas 7"-12" broad, light yellow, their sepals densely canescent, the outer nearly as long as the inner, their capsules ovoid, 1 1/2"-2" long, little if at all overtopped by the later axillary branches; apetalous flowers appearing later, minute, clustered in the axils, nearly sessile, their capsules 1"-1 11/2" in diameter; seeds evenly reticulated.
In dry soil, Nova Scotia to Ontario, South Dakota, Nebraska, Colorado, South Carolina and Texas. Rock-rose. Petaliferous flowers June-July. Helianthemum georgiànum Chapm. (H. propinquum Bicknell) differs in being lower, usually with more numerous stems, the longer-pedicelled petaliferous flowers short-racemose or subcorym-bose, and ranges north from the Southern States into southern New Jersey and Long Island.
Cistus canadensis L. Sp. Pl. 526. 1753. Helianthemum canadense Michx. Fl. Bor. An..
1: 308. 1803. Halimium canadense Grasser, Pflanzenreich 14: 51. 1903.
Puberulent-canescent, erect, ascending, or sometimes diffuse, 3'-2° high, stem at first simple, later with slender elongated branches. Leaves oblong, linear-oblong or oblanceolate, nearly sessile, 6"-15" long, 2'-4" wide, rough and dark green above, paler and canescent beneath, the margins commonly revolute in drying; petaliferous flowers solitary, or rarely 2, bright yellow, 9"-2o" broad, their sepals pilose, the outer shorter than the inner, their capsules ovoid or obovoid, rounded above, 3"-4" long, much overtopped by the later elongating axillary branches; apetalous flowers appearing later, axillary, nearly sessile, their capsules about 2" in diameter; seeds papillose.
In dry rocky or sandy soil, Maine to Ontario, Indiana and Wisconsin, south to North Carolina and Mississippi. Petaliferous flowers May-July. In late autumn crystals of ice sometimes shoot from the base of the stem in this and the preceding species, whence the popular name frost-weed. Canadian rock-rose.
Helianthemum corymbosum Michx. Fl. Bor. Am. 1: 307. 1803.
Erect, branching from the base, 6'-12' high, finely and densely canescent. Leaves oblong, or the lowest obovate, 10"-16" long, obtuse or acutish, 3"-5" wide, entire, slightly revolute in drying, pale beneath, dark green above, short-petioled; flowers in nearly naked, fas-tigiate cymes at the summits of the stem and branches; the petaliferous 6"-10" broad, on slender pedicels 6"-8" long; apetalous flowers clustered, nearly sessile; calyx of both kinds woolly-pubescent; outer sepals about equalling the inner; capsules of the larger flowers 2"-3" broad, many-seeded; those of the apetalous ones smaller and few-seeded.
In sandy soil, New Jersey ( ?), North Carolina to Florida and Louisiana.