440 CISTACEAE. (Von, Il. 
2. Helianthemum Canadénse (L.) Michx. Long-branched Frostweed. 
Frost-wort. (Fig. 2471.) 
Cistus Canadensis \,. Sp. Pl. 526. 1753- 
Helianthemum Canadense Michx. F1. Bor. 
Am, I: 308. 1803. 
Puberulent-canescent, erect, ascending, 
or sometimes diffuse, 3/-2° high, stem at 
first simple, later with slender elongated 
branches. Leaves oblong, linear-oblong ay 
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’’-15’’ broad, their sepals 
pilose, the outer shorter than the inner, 
their capsules ovoid or oboyoid, 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 Indiana 
and Wisconsin, south to North Carolina and 
Kentucky. 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. Called also Canadian Rock Rose. 
3. Helianthemum corymbosum 
Michx. Pine-barren Frostweed. 
(Fig. 2472.) 
Helianthemum corymbosum Michx. Fl. Bor. 
Am, I: 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, fastigiate cymes at the sum- 
mits of the stem and branches; the petalifer- 
ous 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; cap- 
sules of the larger flowers 2//-3’’ broad, 
many-seeded; those of the apetalous ones 
smaller and few-seeded. 
In sandy soil, Virginia (?), North Carolina to 
Florida and Louisiana. Reported from New 
Jersey, but specimens so-called prove to be #7. 
Canadense. 
2, HUDSONIA L. Mant. 11.1767. 
Low tufted diffusely branched shrubs, with small subulate or scale-like, imbricated 
leaves, and numerous yellow flowers terminating short branches. Petals 5, obovate-oblong. 
Stamens o. Style filiform, continuous with the ovary; placentae 3; stigma minute. Cap- 
sule 3-valved, included in the calyx. Seeds few; embryo slender, spirally curved. [Named 
for Wm. Hudson, 1730-1793, an English botanist. ] 
A genus of 3 species, natives of eastern North America, one inhabiting mountain tops in North 
Carolina. Plants of heath-like aspect, very showy when in bloom. 
Flowers slender-pedicelled; leaves subulate. 1. H. ericoides. 
Flowers nearly sessile; leaves scale-like. 2. H. tomentosa. 
