126 PUBLIC HEALTH BULLETIN NO. 286 



5. Lythrum L. 



1. Stem creeping; leaves mostly opposite 1. L. flagellar e. 



I. Stem erect; leaves mostly alternate 2. 



2. Leaf-blades rounded or cordate at base 2. L. alatum. 



2. I>eaf-blades narrowed at the base 3. 



3. Leaf-blades thick, numerous, and less than 1.5 cm. long 3. L. lanceolatum. 



on branches. 

 3. Leaf-blades thin, few, and over L5 cm. long on branches. 4. L. curlissii. 



1. L. Uagellare Shuttlw. — Swamps in lower peninsular Florida. 



2. L. alatum Pursh — Swamps in various provinces over all of our 

 territory except perhaps Florida. 



3. L. lanceolatum Ell. — Coastal Plain, Florida north to South 

 Carolina and west to beyond the limit of our area, mostly in alluvial 

 situations. 



4. L. curtissii Fernald — Known only from muddy and often 

 calcareous swamps, North Florida and the immediately adjacent 

 portion of South Georgia. 



ONAGRACEAE Evenmg primrose family 



1. Ludwigia L 



1. Leaves opposite 2. 



1. Leaves alternate 4. 



2. Flowers sessile; corolla inconspicuous 3. 



2. Flowers with long stalks; corolla conspic- 1. L. arcuata. 

 uous. 



3. Calyx tube usually bearing one or more long bracts 2. L. natans. 

 above base; calyx tube without 4 longitudinal green 

 bands. 



3. Bract, when present, borne basally; calyx tube with 3. L. paluslris. 

 4 longitudinal green bands. 



4. Flowers showy, stalked 4. L. alternifolia. 



4. Flowers mostly not showy, sessile 5. 



5. Petals wanting or minute 6. 



5. Petals as long as the sepals or longer, showy 15. 



6. Capsule 1-3 mm. long, plants sometimes de- 7. 

 pressed. 



6. Capsule 3-8 mm. long, plants erect 8. 



7. Plant depressed; leaves entire 5. L. microcarpa. 



7. Plant ascending; leaves toothed near the apex 6. L. curtissii. 



8. Capsule about as thick as long, not cylindric. 9. 



8. Capsule much longer than thick, cjlindric..- 7. L. glandulosa. 



9. Foliage and fruit copiously pubescent 8. L. pilosa. 



9. Foliage and fruit glabrous or nearly so 10. 



10. Inflorescence terminal 9. L. suffruticosa. 



10. Flowers distributed over plant 11. 



II. Capsules turbinate or obpyramidal but not globular.. 12. 



11. Capsule globular 10. L. sphaerocarpa. 



12. Capsule with the angles rounded or merely 13. 



square. 



12. Capsule with Ihe angles winged or at least 14. 

 margined. 



