CISTACEAE (liOCKROSE FAMILY) 577 



The large flowers open only once, in sunshine, and cast their petals by the next 

 day. (Name from T}\IOS, the sun, and AvOf^v, flower.) 



1. H. canad6nse (L. ?) Michx. (FROSTWEED.) Erect, hoary-pubescent, 3-5 

 din. high, at first simple ; leaves lance-oblong, pale beneath ; large flowers 

 solitary, 2.5 cm. broad, soon surpassed by lateral branches, their pods 6 mm. 

 long ; the small flowers clustered on short 1-4-flowered branchlets^ their pods 

 light brown, unequal, those of the terminal flowers commonly larger, 3-4 mm. 

 in diameter. Sandy or gravelly dry soil, Me. to Mich., N. C., and Miss. Jurie- 

 Aug. Late in autumn crystals of ice shoot from the cracked bark at the base 

 of this and the next species, whence the popular name. A dwarf and rather 

 more cespitose plant with crowded stems only 1-2 dm. high, common on ster- 

 ile shores and sandy hills near the sea, from e. Mass, southw. (H. propinquum 

 Bicknell) appears to be only a stunted form of this species. 



2. H. majus BSP. (FROSTWEED.) Similar in habit and more canescent ; 

 primary flowers clustered at the summit of the stem, not surpassed by branches ; 

 petals slightly paler yellow than in the preceding ; secondary flowers very small, 

 numerous, closely clustered along slender branches, their pods dark brown, 2 

 mm. in diameter. Similar situations, N. S. to Minn., Col., and southw. This 

 is H. majus BSP., at least in part, and of recent auth. It seems probable, 

 however, that Lechea major L. represented rather the preceding species. Until 

 the Linnean types both of Cistus canadensis and of Lechea major can be 

 definitely identified, it seems best to allow the current interpretation of the 

 names under Helianthemum to stand as above. 



3. H. corymbbsum Michx. Flowers all corymbosely clustered at the summit 

 of the stem or branches, the petal-bearing ones at length on slender stalks ; 

 calyx woolly. Pine barrens, N. J. , and southw. along the coast. 



2. HUDS6NIA L. 



Petals much larger than the calyx. Style long and slender ; stigma minute. 

 Pod terete, inclosed in the calyx, strictly 1-celled, with 1 or 2 seeds attached 

 near the base of each nerve-like placenta. Embryo coiled into the form of a 

 closed hook. Bushy heath-like little shrubs, covered with the small awl-shaped 

 or scale-like alternate persistent downy leaves, producing numerous small but 

 showy bright yellow flowers crowded along the upper part of the branches. 

 (Named in honor of William Hudson, an early English botanist.) 



1. H. ericoides L. Downy but greenish ; leaves slender, awl-shaped, loose; 

 flowers on slender naked stalks; ovary hairy. Dry sandy soil near the coast, 

 Nfd. to Va. May. 



2. H. tomentosa Nutt. Hoary with down ; leaves oval or narrowly oblong, 

 2 mm. long, close-pressed and imbricated ; flowers sessile or nearly so. Sandy 

 shores, dunes, etc. , N. B. to Va., and along the Great Lakes to Minn. ; rarely 

 on banks of streams inland. May, June. Passing into var. INTERMEDIA Peck. 

 Leaves tending to be more awl-shaped; flowers obviously peduncled. Sand 

 hills, etc., e. Que. to Mackenzie, s. to e. N. B., Saco Valley, Me. and N. H., 

 shores of L. Champlain, Vt., and the Great L. region. 



3. LECHEA [Kalm] L. PINWEED 



Stigmas 3, plumose. Pod globular or obovoid. Embryo straightish. Slen- 

 der erect paniculately branched perennial herbs, developing leafy shoots from 

 the base. Flowers very small, greenish or purplish, in summer. (Named in 

 honor of Johan Leche, a Swedish botanist.) 



Leaves of the basal shoots elliptical or oblong. 

 Pubescence of the stem spreading ; panicle of small dense corymbose 



clusters 1. L. villosa. 



Pubescence of the stem appressed ; panicle more open. 



Outer sepals exceeding the inner . . 2. L. minor. 



Outer sepals shorter than the others. 



GRAY'S MANUAL 37 



