440 



CISTACEAE. 



[VOL. II. 



2. Helianthemum Canadense (L,.) Michx. Long-branched Frostweed. 



Frost-wort. (Fig. 2471.) 



Cistus Canadensis L. Sp. PI. 526. 1753. 

 Helianthemum Canadense Michx. Fl. Bor. 



Am. x: 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 

 or oblanceolate, nearly sessile, 6 / '-i5 // 

 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"-i5" broad, their sepals 

 pilose, the outer shorter than the inner, 

 their capsules ovoid or obovoid, rounded 

 above, $"-$" 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. "3" 



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 corymbdsum 



Michx. Pine-barren Frostweed. 



(Fig. 2472.) 



Helianthemum corymbosum Michx. Fl. Bor. 



Am. 1:307. 1803. 



Erect, branching from the base, 6'-i2' 

 high, finely and densely canesccut. Leaves 

 oblong, or the lowest obovate, ic^'-io" long, 

 obtuse or acutish, 3"-5" wide, entire, 

 slightly revolute in drying, pale beneath, 

 dark green above, short- pctioled; flowers in 

 nearly naked, fastigiate cymes at the sum- 

 mits of the stem and branches; the petalifer- 

 ous 6"-io // 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 H. 

 Canadense. 



2. HUDSONIA L. Mant. u. 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 co. 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 

 forWm. 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. i. H. ericoides. 



Flowers nearly sessile; leaves scale-like. 2. H. tomentosa. 



