EPILOBIACEAE 835 



1. ISNARDIA L. 



Succulent herbs. Stems creeping or floating. Leaves opposite, relatively few : blades 

 more or less petioled. Flowers axillary, sessile. Sepals 4, shorter than the hypanthium 

 or slightly longer. Corolla not yellow. Filaments very short. Ovary very short : style 

 often almost wanting. Capsule obovoid or turbinate, straight, sessile. MARSH PURSLANE- 



Fruit 2.5-4 mm. long : corolla usually wanting. 



Plant pubescent : fruit 2.5-3 mm. long. 1. I. spathulata. 



Plant glabrous : fruit 3-4 mm. long. 2. J. palustris. 



Fruit 6-7 mm. long : corolla usually present. 3. L natans. 



1. Isnardia spathulata (T. & G.) Small. Stem diffusely branched at the base, the 

 branches 1-3 dm. long, decumbent and creeping, appressed-pubescent : leaf -blades spatu- 

 late or oval, sometimes obtuse, 2-2.5 cm. long, winged, petioled : flowers inconspicuous, 

 hypanthium densely pubescent : sepals 4, broader than high or as broad as high : petals 

 wanting: caps-ules globose-obovoid or obovoid, 2.5-3 mm. long, obscurely 4-sided, pubes- 

 cent. [Ludwigia spathulata T. & G.] 



Around pine-land ponds, middle Florida. Summer. 



2. Isnardia palustris L. Stems branching, 1-5 dm. long : leaf -blades oval, ovate or 

 spatulate, 12-25 mm. long, narrowed into slender petioles : flowers solitary, about 2 mm. 

 broad : bractlets at base of the hypanthium usually none : sepals triangular, acute : petals 

 small, reddish, or usually wanting : capsules 4-sided, slightly longer than wide, 3-4 mm. 

 long, slightly exceeding the sepals in length. [Ludwigia palustris (L.) Ell.] 



In muddy ditches and swamps, Nova Scotia to Manitoba, Oregon, Florida, California and Mexico. 

 Widely distributed in the Old World. Spring to fall. 



3. Isnardia natans ( Ell. ) Small. Stems creeping or floating, more or less branched, 

 usually diffuse, 1-5 dm. long, glabrous : leaf-blades ovate, elliptic or oval, 1-3 cm. long, 

 petioled, or the lower ones sometimes nearly sessile : sepals 4, ovate-lanceolate, acute : 

 petals 4, as long as the sepals, inconspicuous : capsules inversely pyramidal, 6-7 mm. long, 

 4-sided. [Ludwigia natans Ell.] 



In streams and marshes, North Carolina to Florida and Mexico. Spring to fall. 



2. LUDWIGIANTHA Small. 



Fleshy herbs. Stems prostrate, creeping. Leaves opposite, numerous : blades sessile. 

 Flowers on slender bracted peduncles. Sepals narrow, longer than the hypanthium. 

 Corolla yellow. Petals conspicuous, ^surpassing the sepals. Filaments elongated. Ovary 

 relatively long : style filiform, elongated. Capsule club-shaped, curved at the base, sur- 

 mounted by a 4-lobed stylopodium, about as long as the persistent sepals. 



1. Ludwigiantha arcuata (Walt.) Small. Stems glabrous or nearly so, 8-30 cm. 

 long. Leaf -blades oblanceolate, leathery, smooth, obtusish at the apex, narrowed at the 

 base, 12-25 mm. long : flowers axillary, solitary : sepals linear-lanceolate, acuminate, 

 shorter than the obovate petals : corolla bright yellow, 8-12 mm. broad : capsules club- 

 shaped, somewhat curved, glabrous, 8-10 mm. long. \_Ludwigia arcuata Walt.] 



In swamps, Virginia to Florida. Spring and summer. 



3. LUDWfGIA L. 



Perennial or annual herbs. Stems erect or ascending, sometimes angled or winged. 

 Leaves alternate : blades usually entire. Flowers axillary or terminal. Sepals generally 

 persistent. Petals usually 4. Stamens usually 4. Ovary 4-5-celled. Capsule terete, 

 ribbed or winged, septicidal, or opening by an apical pore. 



Corolla inconspicuous, obsolete or wanting : valves of the capsule separating from the disk-like top. 

 A. Petals wanting or minute, shorter than the sepals. 

 Capsules 1-2 mm. long : stem-leaves of a spatulate type. 



Leaf-blades entire. 1. L. microcarpa. 



Leaf-blades toothed near the apex. 



Leaf-blades broadly spatulate: sepals much shorter than the hypanthium. 2. L. Simpsontt. 

 Leaf-blades narrowly spatulate: sepals about as long as the hypanthium. 3. L. Curtissii. 

 Capsules 3-8 mm. long : stem-leaves not spatulate. 

 a. Capsules about as thick as long, not cylindric. 



* Foliage and fruit glabrous or merely appressed-puberulent. 



Flowers in a terminal head or congested panicle. 4. L. suffruticosa. 



Flowers in elongated interrupted spikes or axillary. 

 f Fruit turbinate, cubic-turbinate or obpyramidal. 



Fruit slightly longer than broad, the angles rounded or 

 merely square. 



