192 Rhodora [NOVEMBER 
Potamogetons of the British Isles,! this species, P. vaginatus, has its 
stigma not terminal but, rather, laterally and asymmetrically placed. 
There is some variation in this character, but it occurs in fruits from 
the same spike, rather than definitely on separate plants from distinct 
regions. This makes it clear that the large-sheathed species with 
many whorls of fruit, described from the northern part of North 
America as P. moniliformis St. John, cannot on any character be 
separated from the Eurasian plant. P. moniliformis St. John is, 
then, a synonym of P. vaginatus Turez., a rare and local, but typically 
circumpolar plant which should be sought in the waters of all the 
cooler parts of the northern hemisphere. 
Whether the name Potamogeton marinus L. or P. filiformis Pers. 
should be adopted for the northern setaceous-leaved species is a 
question that has constantly recurred. The writer 2 in 1916 discussed 
the point and concluded that the name P. filiformis Pers. would have 
to be adopted. In the Herbarium at the Jardin des Plantes, Paris, 
is a sheet of this species collected by Nolte. On the ticket he has 
written a full synonymy with page references, and a discussion of the 
pros and cons. Since Nolte has frequently been accredited the 
authorship of the name P. filiformis, this bit of evidence seems worth 
quoting. 
“P. pusillum Boccon. dubiae 
P. setaceus Schumacher 
P. filiformis Pers. 
Nolte; Chamisso & Schlechtendal, [ete.] 
Monsieur Fries pretend la recontraidre Linné Potam. marin! 
Oeder: ete. fl. Dan. pretend que le pectinatum soit le Potam. marin. 
Hartmann pretend que la plante que Monsieur Fries a nommé 
Potam. zosteraceus soit le marinus. 
je m’excuse au P. marin!” 
It is clear, then, that Nolte decided that P. marinus L. could not 
be exactly identified and that P. filiformis Pers. must be adopted 
as the name of this species. 
SOMEWHERE IN FRANCE. 
l Freyer, Pot. Brit. Isl. t. 58 (1915). 
2St. John, Ruopora, vii. 133 (1916). 
