289 
A NEW POTAMOGETON. 
» By Arrsur Benyerr, F.L.S. 
Potamogeton mexicanus, sp. nov. — Rootstock creeping; 
stems simple? Lower leaves 8-5 i in. long, alternate strap- —— 
elliptical, tapering at either end; petioles 8-5 in Upp 
leaves 3-4 in. long, alternate (or pees. opposite) spt 
coriaceous ; wit -16 principal ribs, and oc sap ondar 
eolation distinct over the whole leaf; pebelan 2-6 in 
long {sirls rind be pe 2 in. long, slightly thickening 
upwards. — ing s —- in. ge as er few-fi be nea 
mn fe) 
a to the central marginal edge. Embryo curved for half 
its th. 
Mexico. “ ere de Mexico ; leg. Schmitz (herb. Auerswald),” 
Herb, Mus. Brit.! In flumine bei Chasselte tepec, Aug. et 
ex herb. Be Gohuatines No. 199, affinis P. natans,” Herb. 
Berolien 
The pict in the British Museum Herbarium is not com- 
plete, but the fruit is exactly that of Schnaffner’s plant, which is a 
fairly complete re As yet I have found nothing like this 
at the Kew Herbari 
One of the many 7 plank with leaves very like those of P. fluitans 
th, many of. — cannot t_be determined, from the absence 
American species, it may be well to name 
& species which must, I think, cease to bear the nen given to it 
by Prof. Tuckerman, i. e., P. Claytonii. Chamisso, in Linnea, 
1827, p. 227, described a plant from Willdenow’s havbastn um as P. 
pensylvanicus Willd. hb. n. 8192; and in Willdenow’s herbarium at 
Berlin there are specimens named by Chamisso, and initialled by 
Prof. Tuckerman as his Claytonii, so there is no question that both 
are the same; and I * not see how Chamisso’s name can be 
suppressed. Tuckerman’s name bears date, ‘ Silliman’s Journal of 
Science,’ 1st series, v. 45, p. 88 (1843). 
Journat or Borany.—Vow. 25. [Ocr., 1887.] u 
