ONAGRACEAE 



463 



i. isnardia. 



2. ludwigiantha. 



3. ludwigia. 



4. Chamaenerion. 



5. Epilobium. 



3. R. aristosa Britton. In sandy pine-barren swamps: N. J., 

 Del. and S. Car. 

 N. J. Egg Harbor City, and Cologne, both in the pine-barrens. 



Isolated very locally on the Beacon Hill Formation in the Tertiary 

 region. 



ONAGRACEAE 



Floral whorls of 4 parts or more. 



Fruit a many-seeded capsule, opening by valves or by a pore. 

 Calyx-tube not prolonged beyond the ovary. 

 Seeds naked. 



Leaves opposite; stems creeping or floating. 

 Flowers sessile; petals none or very small. 

 Flowers long-stalked; petals conspicuous. 

 Leaves alternate; stem erect or ascending. 

 Seeds furnished with a tuft of silky hairs. 

 Calyx-tube prolonged beyond the ovary. 



Seeds furnished with a tuft of silky hairs. 

 Seeds naked or sometimes tuberculate. 

 Stamens equal in length. 



Ovules and seeds horizontal, prismatic, 



angled. 

 Ovules and seeds ascending, not angled. 

 Stamens unequal in length, the alternate ones 

 longer. 

 Fruit indehiscent, nut-like. 

 Floral whorls of 2 parts. 



i. Isnardia L.* 

 1. I. palustris L. In muddy ditches and swamps: N. S. to Man., 

 Ore., Fla., Col. and Mex. Widely distributed in the Old 

 World. 



Scattered throughout the range, but rare in the pine-barrens and 

 perhaps introduced. 



2. Ludwigiantha Small.* 

 1. L. brevipes Long. Moist sand: St. Albans, Long Beach Island, 

 Ocean Co., N. J. 



3. Ludwigia L.* 



Flowers inconspicuous; petals none or small, yellowish or greenish. 

 Capsules sub-globose or top-shaped. 



Bractlets at base of calyx minute, or none; capsule finely 



hairy. 1. L. sphaerocarpa. 



Bractlets at base of calyx linear, about equalling the 



glabrous capsule. 2. L. polycarpa. 



Capsules cylindric or obpyramidal. 3. L. linearis. 



* See footnote, page 76. 



