ONAGRACEAE. 



[VOL. II. 



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. 16. Galpinsia. 

 Calyx-tube shorter than the ovary; stigma disk-like, slightly 4-toothed. 



17. Meriolix. 

 Stamens unequal in length, the alternate longer. 



Ovules and seeds many, clustered, on slender funiculi; capsules 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. Pachy 'tophus. 

 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. 



i. ISNARDIA L. Sp. PI. 120. 1753. 



Annual or perennial succulent herbs. Stems prostrate or decumbent, creeping or float- 

 ing; leaves opposite, fleshy, narrowed into petioles which are slightly shorter than the 

 blades. Flowers perfect, axillary, sessile, commonly apetalous. Calyx turbinate, its seg- 

 ments 4, shorter than the tube or slightly longer, persistent. Petals none, or 4, incon- 

 spicuous. Stamens 4; filaments very short; anthers ovoid or oblong. Ovary 4-celled, very 

 short; styles often almost wanting; stigma 4-lobed; ovules numerous, in several rows. Cap- 

 sule 4-angled, obovoid or turbinate, straight, flat at the apex, septicidal. Seeds numerous, 

 often tranversely wrinkled. [In honor of Antoine Dante Isnard, a French botanist, and 

 a member of the Academy of Sciences, died 1724.] 



About 4 species in North America and Mexico. 



x. Isnardia palustris L. Marsh 

 Purslane. (Fig. 2555.) 



Isnardia palustris L. Sp. PI. 120. 1753. 

 Ludwigia palustris Ell. Bot. S. C. x: 211. 



1817. 



Procumbent or floating, glabrous, root- 

 ing at the nodes, succulent. Stems 

 branching, 4'-i5' long; leaves opposite, 

 oval, ovate or spatulate, acute or obtuse 

 at the apex, 6"- 12" long, narrowed into 

 a slender petiole; flowers axillary, soli- 

 tary, sessile, about i" broad; bractlets at 

 base of the calyx usually none; calyx 

 lobes triangular, acute; petals small, red- 

 dish or often wanting; capsule 4-sided, 

 slightly longer than wide, about l%" 

 high, slightly exceeding the calyx lobes. 



In muddy ditches and swamps, Nova Scotia 

 to Manitoba and Oregon, Florida, Louisiana, 

 California and Mexico. Widely distributed 

 in the Old World. Also called False Loose- 

 strife, Water Purslane. June-Nov. 



2. LUDWIGIANTHA Small, Bull. Torr. Club, 24: 178. 1897. 

 Annual or perennial fleshy herbs. Stems prostrate, creeping, usually little branched; 

 leaves opposite, sessile, leathery, numerous. Flowers perfect, yellow, on slender bracted 

 peduncles which are 2-3 times longer than the leaves. Calyx narrowly obconic, its 4 seg- 

 ments narrow, longer than the tube. Petals conspicuous, surpassing the calyx-segments. 

 Stamens 4; filaments elongated, very slender; anthers ovoid. Ovary 4-celled; united styles 

 filiform, elongated; stigma 4-lobed; ovules numerous. Capsules club-shaped, curved 



