AND SERPICULA OCCIDENTALIS. 



79 



I have been long engaged in studying the Anachar idea, for the purpose 

 of ascertaining the distribution of the plant of the Dammschen Sea, 

 and have found that Koch knew all about it ; it is essentially different 

 from the American Serpicula occidental^ which was collected by Moser 

 near Bethlehem, in Pennsylvania, and of which I have examined and 

 identified specimens in the Herbaria of Vienna, Leipsic, J. Gay, and 

 Sir W. Hooker. The diagnoses of the species are as follows : 



Serpicula occidentalism Pursh. 



1. Serratures of the leaves of only 



one cell. 



Udora occidentalism Koch. 



1. Teeth (not serratures) of the leaves 

 with several (three to eight) cells. 

 2. Stipulse intrafoliacese very minute 2. Stipuhe intrafoliacea? oblong or ob- 



(hitherto overlooked in both species), long-lanceolate, and wrinkled on the 



margin with long, linear papillae. 



3. At the base of the branches is a 

 solitary, amplexicaul leaf, with its back 

 to the axis. 



The whorls of leaves of the middle of the American plant are further 

 only three-fold, or rarely four-fold, whilst in the Pomeranian plant they 

 are four- to sevenfold, seldom three- or eight-fold : this last difference 



ovate or almost quite orbicular. 



3. At the base of the branches are 



two equal, triangular, ovate, opposite 

 leaves. 



Eeichenbach has well pointed out. 



I find further that the Hydora Lithuanica, Andrz. (Besser in Flora, 

 1832, No. 1, p. 12), from the neighbourhood of Wilna, in Lithuania, 

 agrees with the plant of the Dammschen Sea in the above points and 

 in others of less importance, and that the Stettin plant has no affinity 

 with the American plant, but is identical with the Serpicula verticillata , 

 of which I saw the original specimen in the Linnean Herbarium in 

 London, and which is found in the East Indies, Ceylon, Java, China, 

 Australia, and the Mauritius, but under several different forms. 



Claude Eichard has properly separated the Serpicula verticillata from 

 that genus (whose first described species is a native of South Africa, 

 and belongs to Haloragece), and has called it Hydrilla ovalifolia, placing 

 it amongst Hydrockaridea. The name ovalifolia was however derived 

 from a rather uncommon form, with short leaves, and was hence inap- 

 propriate to the whole species ; and the specific name of verticillata 

 having been indiscriminately applied by Linn, fil., Sprengel, Muhlen- 

 berg, Hooker, and others, to all the species, induced me to reject it 

 also, following a common practice, and to give that of Hydrilla dentata 

 (from the characteristic toothing of the leaves). But there is another 



