486 PROCEEDINGS OP THE AMERICAN ACADEMY. 



achene of the European E. ovata (Figs. 9, 10) is obovate or inverted- 

 pyriform in outline, and it is about three fourths as high and two thirds as 

 broad as the obovate or cuneate-obovate achene of the typical American 

 plant (Figs. 4 to 7) which commonly passes under that name. The 

 tubercle of true £J. ovata averages four sevenths as broad as the achene, 

 while that of the American plant equals the achene in breadth. Though, 

 as already stated, the European . E. ovata and the American plant 

 recently united with it are not readily distinguished by superficial 

 characters, the apparently constant differences in their achenes and 

 tubercles are sufficient to justify us in regarding our own plant as dis- 

 tinct from that of Europe, and in restoring to it the distinctive name 

 Eleocharis obtusa, under which it was so long known to American 

 botanists. 



Although the common Americiin plant, which, for the last three de- 

 cades, has passed as Eleocharis ovata, proves on critical study to differ 

 from that species in certain well marked and constant characters, the true 

 jEJ. ovata of Europe is not entirely wanting in our American flora. The 

 American plant, however, which not only in habit but in the characters 

 of achene and tubercle closely matches the European specimens and 

 plates, is as yet known from only four northern stations, in New Bruns- 

 wick, Maine, Vermont, and Mioliigan. In these specimens, in habit and 

 achenes undoubtedly E. ovata, the oblong or ovate-oblong scales are 

 very dark chestnut-brown or purplish, distinctly darker than is usual in 

 E. obtusa. 



In October, 1878, Mr. E. H. Hitchings collected in Dedham, Massa- 

 chusetts (presumably in Purgatory Swamp), an Eleocharis which has 

 proved unusually puzzling to those who have subsequently worked upon 

 the genus. Two sheets of the plant, showing large and small specimens, 

 are preserved in the Gray Flerbarium, where they have been frequently 

 shifted from one species cover to another. Originally Dr. Gray wrote 

 upon one of the sheets, a " remarkable form, I think, of Eleocharis inter- 

 media." Subsequently both sheets were referred by Dr. Watson to 

 E. obtusa ; but when studying the plants in the prejmration of his synop- 

 sis of "The Genus Eleocharis in North America," ^ Dr. N. L. Britton re- 

 ferred the two Dedham sheets to different species, the smaller specimens 

 to E. olivacea, the other to E. palustris. Why the two sheets should be 

 thus separated we cannot make out. They are, to be sure, hardly iden- 

 tical in size, but in general habit, scales, and achenes they are the same, 



1 Jour. N. Y. Microsc. Soc, V. 95-111. 



