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. L spathulata. 



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



Fruit 6-7 mm. long : corolla usually present. 3. I. 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 : capsules 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. Simpsonii. 

 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. suffruticota. 



Flowers in elongated interrupted spikes or axillary, 

 f Fruit turbinate, cubic-turbinate or obpyramidal. 



g Fruit slightly longer than broad, the angles rounded or 

 merely square. 



