54 



CISTACEAE. 



VOL. II. 



i. Crocanthemum majus (L.) Britton. Hoary 

 Frostweed. Fig. 2909. 



Lechea major L. Sp. PI. 90. 1753. 



Helianthemum majus B.S.P. Prel. Cat. N. Y. 6. 1888. 



Halimium majus Crasser, Pflanzenreich 14: 50. 1903. 



Hoary-canescent, stems erect, i-2 high, at first 

 simple, later with numerous short ascending branches. 

 Leaves oblong-lanceolate or oblanceolate, acute or ob- 

 tuse, 8"-i8" long, stellate-canescent beneath, darker 

 above, short-petioled ; petaliferous flowers 5-12 in a 

 terminal cymose raceme, their corollas 7"-i2" broad, 

 light yellow, their sepals densely canescent, the outer 

 nearly as long as the inner, their capsules ovoid, ii"-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 

 i"-ii" in diameter; seeds evenly reticulated. 



In dry soil, Nova Scotia to Ontario, South Dakota, Ne- 

 braska, Colorado, South Carolina and Texas. Rock-rose. 

 Petaliferous flowers June-July. 

 Helianthemum georgianum 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. 



2. Crocanthemum canadense (L.) Britton. Long-branched Frostweed. Scrofula- 

 plant. Rock-rose. FrosMvort. Fig. 2910. 



Cistus canadensis L. Sp. PI. 526. 1753. 

 Helianthemum canadense Michx. Fl. Bor. Aii. 



i : 308. 1803. 

 Halimium canadense Crasser, Pflanzenreich 



14: 51. 1903. 



Puberulent-canescent, erect, ascending, or 

 sometimes diffuse, 3'-2 high, stem at first 

 simple, later with slender elongated branch- 

 es. Leaves oblong, linear-oblong or oblan- 

 ceolate, nearly sessile, 6"-i5" long, 2"-4" 

 wide, rough and dark green above, paler 

 and canescent beneath, the margins com- 

 monly revolute in drying ; petaliferous flow- 

 ers solitary, or rarely 2, bright yellow, 

 p"-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 appear- 

 ing later, axillary, nearly sessile, their cap- 

 sules about 2" in diameter; seeds papillose. 



In dry rocky or sandy soil, Maine to On- 

 tario, 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. 



