121 



part to the ends <>l the long unbranched stem, the numerous 

 fruits remaining conspicuously on the leafless parts. It is as- 

 sumed that the stems become more or less erect during high 

 water, with the cluster of leaves reaching nearly or quite to the 

 surface. The fruits appear somewhat thicker than usual in L. 

 palustris and contain large white to straw-colored seeds (averag- 

 ing 0.7-0.8 mm. long 8 ); the cinnamon-colored to brown seeds 

 of the plants of northern United States and of Europe run 

 from 0.5-0.65 mm. and very rarely 0.7 mm. in length. Most of 

 the estuarine plants were exceptionally robust, the stems ex- 

 ceeding 3 dm. in length, but even minute plants only a few 

 centimeters high had seeds 0.7 mm. long. The flowers were 

 minute even for this species with extremely small flowers, a 

 reduction undoubtedly paralleling that in other estuarine 

 plants, for example Ilysanthes dubia var. inundata. 



This material was strikingly similar to previous collections 

 made by me at Coeymans on the opposite shore of the Hudson 

 River, 1932, and from Chesapeake Bay, and this fact suggested 

 that the same type of plant ought to occur in the estuary of the 

 Delaware River. Through the kindness of Dr. Pennell, I have 

 examined specimens from the herbarium of the Philadelphia 

 Academy of Natural Sciences and it is from this material that 

 I have cited stations for var. inundata from New Jersey and 

 Pennsylvania. 



It is obvious that this variety is not the same as L. palustris 

 (L.) Ell. f. submersa (Gluck) E. H. Eames (Rhodora 35: 229. 

 1933) which was a renaming of the sterile branched deepwater 

 form of Europe. I do not believe that it can be associated with 

 the poorly defined Isnardia palustris (3 americana DC. (Prod. 3 : 

 61. 1828) differentiated only by "foliis untrinque magis acumi- 

 natis" and based primarily upon plants from southern United 

 States. 



Although small purplish rudimentary petals were reported 

 in Ludvigia palustris by Torrey (Fl. N. V. 1 : 238. 1843) and have 

 been mentioned by subsequent writers, no sign of such struc- 

 tures, with a single exception, has been observed by me in exam- 

 ination of a large amount of material. In a collection of L. palus- 

 tris by E. J. Palmer (no. 12235) from Kerr County, Texas, four 



3 Average measurements were obtained from ten seeds. 



