540 



CISTACEAE. 



Vol. II. 



Helianthemum georgianum Chapm 



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. 

 . (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. Frost^wort. Fig. 2910. 



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

 Helianthemum canadense Michx. Fl. Bor. Aii.. 



i: 308. 1803. 

 Halimium canadense Crasser, Pflanzenreich 



14: SI. 1903. 



Puberulent-canescent, erect, ascending, or 

 sometimes diff^use, 3'-2° high, stem at first 

 simple, later with slender elongated branch- 

 es. Leaves oblong, linear-oblong or oblan- 

 ceolate, nearly sessile, 6"-is" 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, 

 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 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. 



