65 
Original Articles. 
TWO NEW POTAMOGETONS. 
By Arraur Bennett, F.L.S. 
(Tax. 235.) 
Potamogeton Griffithii, n, sp.—Stem branched, 2-8 ft. long. 
Lower leaves alternate, sessile, slightly clasping, strap-shaped, 
none 9 the apex when ‘fre sh, entire, slightly undulated, 11-veined, 
4-5 fainter veins close to the midrib, sons eatabaieet Upper : 
(doating) leaves opposite, long-stalked, oblanceolate, gradually 
attenuated into the long petiole, 18-17 veined with distinet 
enlarged towards the centre. Spike cylindrical, he flowered. 
Sepals roundish-oval, broader than long. Young fruit oval, with 
the k lene the continuation of the inner edge. Ripe 
fruit not seen ibmerged leaves tinged with yellowish brown. 
floating lea green. Lower vaste ge 7-12 in. long, 4-2 in. 
broad ; laming of the —— leaves rae jong, Ait 2-4 in, 
Spike 3-1 
ong. 
The plant has the habit of P. prelongus wae i) floa oating 
leaves much resemble those of the N. America vt Tuck. ; 
the submerged, those of P. longifolius Bab. (not “of Gay 4 2 ee apex 
of the leaves in P. Griffithii is decidedly boat-shaped, although not so 
much so as represented in the plate. i examined most of the broad- 
leaved Potamogetons in a fresh state last autumn, to see if there was 
any tendency to this boat-shaped apex of the leaf, but cannot find it 
in any except prelongus and Gr rifithii. There does not seem to be 
any approach to floating leaves in P. prelongus among the numerous 
specimens I have examined from N. pgp ee and Europe; the 
nervation of the leaves and spikes Grifithii is also totally 
erent. Hab. Llyn-an-Afon tie age ‘a locally as Aber taki, 
near Aber, Carnarv proiahive, orth Wales, alt. 1250 feet. June, 
August, October, 1882. Mr. J. E. Griffith. 
W . Griffith sent me the first specimens I was strongly 
inclined to refer them to P. long gifolius Bab.; but on his visiting the 
locality (which is somewhat difficult of access) twice afterwards, 
and kindly sending me a su ly ‘of specimens in the fresh state 
and with floating leaves, I saw it could not be so referred. Later 
I thought it might. possibly be a hybrid between prelongus and 
r ——. though I am a a opponent of referring every 
uncert ain plant to a hybrid origin; but Mr. Griffith oe 
Vou. 21. [Marcu, 1883.] 
