FLORA. 



styles united ; stigma capitate, discoid or 4-lobed ; ovules generally anat- 

 ropous. Fruit a capsule or small nut. Endosperm very little or none. 

 Forty genera and about 350 species of wide geographic distribution, most 

 abundant in America. 



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. 



Stamens 4, in i row. 



Leaves opposite ; stems creeping or floating. 



Flowers sessile; petals none, or very small ; leaves petioled ; cap- 

 sules sessile, short, the top flat. \. Isnardia. 

 Flowers long-stalked; petals conspicuous; leaves sessile; cap- 

 sules elongated, curved, with a prominent 4-lobed stylopo- 

 dium. 2. Ludivigiantha. 

 Leaves alternate; stems erect or ascending. 3. Ludwigia, 

 Stamens 8-12, in 2 rows. 4. Jussiaea. 

 Seeds furnished with a tuft of silky hairs. 5. Chamaenerion. 

 Calyx-tube prolonged beyond the ovary. 



Seeds furnished with a tuft of silky hairs. 6. Epilobium. 



Seeds naked or sometimes tuberculate. 

 Stamens equal in length. 



Stigma deeply 4-cleft, its segments linear. 



Ovules and seeds horizontal, inserted in 2 or rarely more rows, 



prismatic-angled. 7. Onagra. 



Ovules and seeds ascending, not angled. 



Buds erect ; petals yellow ; ovules and seeds in 2 rows. 



8. Oenothera. 

 Buds drooping ; petals white or pink ; ovules and seeds in 



i row. 9. Anogra. 



Stigmas entire or slightly 4-toothed. 



Calyx-tube longer than the ovary; stigma disk-like, entire. 



1 6. Galpinsia. 

 Caiy X -tube shorter than the ovary; stigma disk-like, slightly 



4-toothed. 17. Meriolix. 



Stamens unequal in length, the alternate ones longer. 



Ovules and seeds many, clustered, on slender funiculi; capsules usu- 

 ally club-shaped. 



Flowers yellow. 10. Kneiffia, 



Flowers white, pink or reddish. n. Hartmannia. 



Ovules or seeds few, sessile, in i or 2 rows. 

 Plants normally acaulescent. 



Capsules obtusely or retusely 4-angled ; seeds furrowed 



along the raphe. 12. Pachylophus. 



Capsules sharply 4-angled or winged ; seeds with a tubercle 



at one end. 13. Lavauxia. 



Plants caulescent. 



Stems wiry, diffuse ; capsules sharply 4-angled. 



14. Gaurella. 

 Stems stout, not diffuse; capsules 4-winged. 



15. Megapterium. 

 Fruit indehiscent, nut-like. 



Calyx-tube obconic; filaments with scales at the base ; ovary 4-celled. 



18. Gaura. 

 Calyx-tube filiform; filaments unappendaged ; ovary i-celled. 



19. Stenosiphon. 

 Floral whorls of 2 parts. 20. Circaea. 



x. ISNARDIA L. 



Succulent herbs. Stems creeping or floating; leaves opposite, relatively few, 

 petioled. Flowers axillary, sessile, not yellow. Calyx-segments 4, shorter than 

 the tube or slightly longer. Filaments very short. Ovary very short; styles often 

 almost wanting. Capsule obovoid or turbinate, straight. [In honor of Antoine 

 Dante Isnard, a French botanist, and a member of the Academy of Sciences, died 

 1724.] About 4 species in N. Am. and Mex. 



i. Isnardia palustris L. MARSH PURSLANE. (I. F. f. 2555.) Stems 

 branching, 1-5 dm. long; leaves oval, ovate or spatulate, 12-25 mm - l n g> nar - 



