CISTACE^E. 29 



ORDER XIII. CISTA'CE^!. (EOCK-ROSE FAMILY.) 



Herbs or low shrubs, with simple entire leaves and regular 

 polyandrous flowers. Calyx persistent, usually of 3 large 

 and 2 smaller sepals. Petals 5 or 3, convolute in the bud. 

 Stamens 3-20. Pod 1-celled, 3-valved. Seeds on 3 parietal 

 projections. 



Synopsis of the Genera. 



1. Helian'thenmm. Petals 5, fugacious. Style none. 



2. lliulso iiia. Petals 5, fugacious. Style long and slender. 



3. Lecli'ea. Petals 3, persistent. Style none. 



1. HELIAX'THEMUIM, Tourn. ROCK-ROSE. 

 H. Canadense, Michx. (FROST- WEED.) Flowers of two 

 sorts, some solitary, with large yellow corolla and many 

 stamens, the petals lasting but one day after the flower 

 opens ; others small, clustered in the axils of the leaves, 

 and apetalous. Leaves lanceolate, downy beneath. Sandy 



places. 



2. HIJDSO'NIA, L. HUDSONIA. 



1. H. tomento'sa, Nutt. (DOWNY H.) Hoary. Leaves 

 oval or narrowly oblong, short, close-pressed, or imbricated. 

 Flowers small, sessile, yellow, very numerous. A little heath- 

 like shrub, on the shores of the Great Lakes and the River 

 St. Lawrence. 



2. H. erieoi'des, L. Downy, but greenish. Leaves slen- 

 der, awl-shaped. Flowers on slender naked stalks. Dry soil, 

 Atl. coast. 



3. LECH'EA, L. PlNWEED. 



1. L. minor, Lam. (SMALLER P.) Flowers inconspicuous, 

 purplish, loosely racemose, on distinct pedicels. Stem 

 slender, rough with appressed scattered hairs, producing 

 radical shoots. Leaves scattered, linear. Pods the size of a 

 pin's head. Dry soil. 



2. L. major, Michx. Stem 1-2 feet high, stout, very 

 leafy, villous with spreading hairs, producing prostrate 

 branches at the base. Leaves elliptical, mucronate. Flowers 

 densely crowded, on very short pedicels. Dry soil, S. W. 

 Ontario. 



