TETRANDR1A TETRAG VNIA. 



DIGYNIA. 



84. HAMAMELIS. Witch-hazle. 



11. virginica : leaves obovate, acute, dentate, cordate, with the sinus 



small. 

 HAB. Moist woods. October November. Shrub 6 12 feet high ; 



leaves alternate, large ; Jlower axillary, clustered, yellow. 



TETRAGYNIA. 

 85. ILEX. Holly. 



I. opaca : leaves ovate, spinous, acute, smooth, flat : fascicles of flow- 

 ers loose, on the base of the younger branches ; peduncles com- 

 pound. 



HAB. Sandy woods. June. An evergreen tree,\0 40 feet high ; 

 leaves coriaceous, shining ; Jlower yellow-white ; berries red. 



I. canadensis : leaves deciduous, ovate, very entire, smooth ; peduncles 

 subsolitary, (or fasciculate,) very long, 1-flowered; fruit obtusely 

 subquadrangular. 



HAB. Rocky hills and mountains. May June. Shrub 3 5 feet 

 high ; leaves mucronate ; Jlower dioec., minute ; berries red. 



86. SAGINA. Pearl-wort. 



S. procumbens : perennial ; stem procumbent, smooth ; petals very 



short. 

 HAB. Near springs. July. Spreading 2 4 inches long; leaves 



linear-subul. ; petals sometimes wanting. 



87. POTAMOGETON. Pond-weed. 



* Upper leaves floating. 



P. natans : upper leaves floating ; coriaceous, oblong-ovate, on long 

 petioles, (subcordate ;) lower ones membranaceous, lanceolate, taper- 

 ing to a foot stalk. 



HAB. Lakes and slow streams. July August, f l\.; upper leaves 

 2 3 inches long, 2 broad, nerved; spike greenish. 



P. fluitans : upper leaves floating, coriaceous, oblong-lanceolate, peti- 

 olate, tapering at the base, lower ones linear, sessile. 



HAB. Ponds and slow streams. July August, 1J.; upper leaves 3 

 inches long, 1 broad, olive-green ; peduncle thick. 



P. heterophyllum : upper leaves floating, petiolate, elliptical ; lower ones 

 sessile, crowded, linear. 



HAB. Ponds and slow streams. August, 1}. ; half the size of the 

 preceding ; submerged leaves ver$ narrow. 



