700 Onagraceae Jussiaea 



Flowers yellow (pink or white in Oenothera speciosa) ; fruit not deciduous, dehis- 

 cent 5804. Oenothera, p. 703. 



Flowers light to dark pink; fruit deciduous, indehiscent 5819. Gaura, p. 707. 



Parts of flower in twos; stamens 2; fruit bristly; leaves opposite 



5828. Circaea, p. 709. 



5791. JUSSIAEA L. 



Stems erect; leaves mostly lanceolate, decurrent at the sessile base; petals 4; pod 



4-sided, club-shaped 1- *• decurrens. 



Stems floating or creeping; leaves of an oval type; petals 5; pod cylindric 



2. J. diffusa. 



1. Jussiaea decurrens (Walt.) DC. Map 1472. Primrose- willow. In 

 very wet, sandy soil in the outlet of a spring about 10 miles southwest of 

 Mt. Vernon in Posey County, and on a sandy bar in a small stream in a 

 woods about 4 miles southeast of Hatfield, Spencer County. 



Md. to Fla., westw. to Tex. and up the Mississippi Valley to 111. and Ind. 



2. Jussiaea diffusa Forskal. Floating Primrose-willow. Map 1473. 

 In 1935 I found this species to be common in the artificial lake in Shaka- 

 mak State Park, Sullivan County. I did not investigate how extensively 

 it was established but the border was well stocked with it as far as I 

 traversed it. This lake is artificial and was made only a few years ago. No 

 one seems to know when or how it got its start in the lake. I was in- 

 formed by a workman that aquatic plants had been collected from the 

 sloughs along Eel River and put into the lake. The interesting thing is 

 that this species has so well adapted itself to its new habitat that it now 

 grows abundantly on the shore of a lake which a few years ago was a poor, 

 fallow field. Since no effort will be made to exterminate it, it is established 

 in this place. 



Ind., 111. to Kans., southw. to Fla. and Tex. 



5793. LUDWIGIA L. 



Leaves all opposite 1. L. palustris var. americana. 



Leaves alternate. 



Flowers showy; petals bright yellow; capsules on short pedicels, quadrangular, the 

 angles slightly winged and greenish, the mature ones mostly 4-5 mm wide be- 

 tween the angles; plants more or less pubescent with short, incurved hairs. 



2. L. alternifolia. 



Flowers inconspicuous; petals none or small, yellowish or green; capsules sessile, 

 cylindric, subglobose or obpyramidal, mostly 2-4 mm wide, the angles, if any, 

 rounded, and the sides with a shallow groove. 



Capsules cylindric, about 2 mm in diameter, about twice as long as wide 



3. L. glandulosa. 



Capsules subglobose or obpyramidal, not twice as long as wide. 



Plants glabrous or nearly so; bractlets of the capsules usually as long as or 



longer than the capsules; sepals about half as long as the capsules 



4. L. polycarpa. 



Plants pubescent; bractlets of the capsules usually about half as long as the 



capsules, more rarely minute or up to two thirds as long as the capsules. 



5. L. sphaerocarpa var. Deamii. 



