289 
ON A NEW BRITISH POTAMOGETON OF THE 
NITENS GROUP. 
By Aurrep Fryer, 
(Prate 313.) 
PoramMocETon unputatus Wolfg., v. Coopert mihi = P. crispus x 
P. perfoliatus.—Rootstock with terete stolons, rather shallow rooting. 
tem compressed, stout, somewhat spirally twisted between the inter- 
nodes, obscurely quadrangular, deeply guttered on the broad flattened 
sides, rounded and sometimes obscurely winged on the edges; 
y rt br 
si 
tae springing from the axils of the stem-leaves, which in their 
owth BRNeS axillary stolons terminated by winter-buds, or by 
ung branches. Leaves bright green, undulate, all similar, 
iii cia ts oblong-ovate, or narrowly elongated and “longit itudi- 
nally folded, blunt, cymbiform, often slightly hooded in young 
growths, ascending or reflexed, edges anberensy entire, but finely 
serrulate with very minute persistent spines, 7-ribbed, with 3 
peg nent and 4 faint intermediate ribs oie by ieee 
sree veins. Stipules “gana truncate, soon decaying 
the main stems, subpersistent on the branchlets, with the irre 
subherbaceous, and bearing a sm i adnate leaf; alternate, or 
rarely opposite. Peduncles slender, not thickened above, curved, 
and somewhat aoedrangn le and twisted; spikes short, oh: 
ulatus is intermediate in abit and gee characters 
between ’P. crispus and P. perfoliatus; generally with the facies of 
the latter species, it approaches crispus in its early states, and the 
ae branches often prevent a striking resemblance to those of 
which species, in an aggre gate a: I consider it 
a ” Following the method I adopted in a previous note on 
P. _ area felis, I rank this probable hybrid, with perfoliatus as 0 
as a member of the nitens group, having a — wala “si 
sal 3 that of such forms as P. decipiens Nolte and P. salicifolius 
of the London Cata 
é,€ 
mature state at a glance; but in a young state leaves are some- 
times produced on the upper part of 4g stem which closely resemble 
those of young winter-growths of P. crispus. These leaves, how- 
ever, are more finely serrulate, and are usually less flattened. 
P. nitens v. obovatifolius Tiselius approaches P. Coopert very 
nearly, but may be distinguished in a dried state by its peduncle, 
JouRNAL oF Borany. ee 29. [Oocr. 1891.] U 
e 
