NOTES ON POTAMOGETON _ 71 
on these — I remarked that they could not be referred to 
P, lucens or to P. Zizii, as the former does not produce floating 
leaves, and the floating leaves of these specimens were unlike any 
form of Zizii known to me, while the oe pe did not agree with 
either. I also noted that they reminded me of specimens col- 
lected in 1848, in San Miguel, Azores, by ic T. C. Hunt, which 
were named “ P. lucens?” by Mr. Watson.. ap likeness is 
remarkable, but only superficial. The same plant was gathered 
(but not in flower) by Mr. Trelease in 1894, a from the 
same lagoon in San eae , 
I have not yet been able to name these specimens satisfactorily. 
Coming under duces in a wide sense, they are neither exactly lucens, 
pei or Zizii; Tam inclined to regard them as an endemic 
ety of pis which may be named var. azorica. In habit they 
somewhat resemble the ‘* P. lucens L.” gathered by Gardner 
(No. 2756) in eek which Dr. K. Schumann accepts as lucens in 
who —— the oe plan P. posrn oe occurs in Van- 
Baver's Island and Griffin Lake, associated with a peculiar form 
P. Zizi; but the numerous lakes, lagoons, &c., ng never yet 
een systematically examined. The plant is certainly nearer st 
of which it has the submerged leaves of the narrow-leaved form 
except that the nervation is towards epihydrum; the spikes also are 
Zizi, abet the stipules and floating leaves are almost exactly those of 
epthydru 
. upPsALIENSIsS Tiselius. Dr. Tiselius, in Botaniska Notiser 
(1884), p. 15, identifies his plant with P, salicifolius Wolfg., Roem. 
& Sch., pon ie “ — 1827, and P. samen a Gorski ex Reich. 
Ie. Fl. Germ. v 9 (1845), and Mr. Fry this Journal for 
1890 (p. 138), a ems to coincide with this, view. Ascherson and 
Graebner (Syn. Mitte eleurop. Flor a, Band i. p. 328 (1897) ), on the 
co er i brid— 
P, alpinus x lucens, and di from P. decipiens Nol 
with which Tiselius and Fryer unite it. conc th Ascherson 
and Graebner’s, for I have always felt that if salicifolius was a 
hybrid, alpinus was clearly one of the parents ey have seen 
gang's, and a beautiful series of the upsaliensis of Tiselius; anda 
microscopic — of Wolfgang’s specimens con nfirms this 
view. I believe the matter could be settle d at once if the chemical 
revive the peculiar colouring. If this were present in the slightest 
degree in Wolfgang’s plant | it would decide in favour of P. alpinus 
lucens. 
r. Fryer considers the decipiens of the Cambridgeshire fens to 
be certainly P. lucens x P. perfoliatus, and in this I entirely agree, 
