38 ENGLISH BOTANY. 
SPECIES X—POTAMOGETON LUCENS. Lin. ~ 
Pirates MCCCCVIM. MCCCCIX. 
Stems stout, sparingly branched, the lower branches barren, 
Leaves almost all alternate and submerged, indistinctly stalked or 
subsessile, but not at all amplexicaul, ascending, flat, long, oblong-oval 
or -elliptical or -obovate, narrowed into a more or less distinct petiole 
at the base, acute or obtuse and apiculate or mucronate or with the 
midrib excurrent, not hooded, more or less undulated and irre 
gularly finely serrate at the margins, especially towards the apex, 
translucent, with 11 to 17 longitudinal ribs connected by numerous 
transverse veins,and with a narrow band of elongate cancellate areola- 
tion along the sides of the midrib; upper leaves opposite, similar to 
the eS ones, or more rarely ee floating, and of rather firmer 
texture, but never (?) coriaceous. Sipules lar; ‘ce, blunt, 2-winged on 
the back, subscarious, with numerous strong longitudinal fibres. Pe- 
duncles terminal and axillary, rather short, very stout, thicker than the 
stem, slightly thickened towards the apex in fruit. Sepals with their 
lamina transversely roundish-rhombic. Fruiting-spike dense, cylin- 
drical, many-flowered. Nuts olive, large, slightly acuminated, scarce 
compressed, nearly straight along the upper margin, semicircular a 
not decidedly keeled on the back, terminated by a short beak formi 
a continuation of the upper margin. Plant bright green or olive, retain: 
ing its colour when dry; the ee apie oiae siinine. : 
Var. a, genuinus. 
Prare MCCCCVIII. 
Reich. Ic. Fl. Germ. et Helv. Vol. VII. Tab. XXXVI. Fig. 64. 
Billot, F\. Gall. et Germ. Exsice. No. 2382. 
P. lucens, Auct. Plur. 
Leaves distinctly stalked, apiculate or shortly mucronate, se 
at the margins. Peduncles about as long as the spikes or not m 
than twice as long. 
Var. 8, acuminatus. 
Reich. Ic. Fl. Germ. et Helv. Vol. VII. Tab. XI. Fig. 69. 
P. acuminatus, Schum. “ Enum, Fl. Saelland, vol. i. p. 49.” \ Teste Reich, 1c. p. 98s 
P. cornutum, “ Presl. Fl. Cech. p. 37.” 
Leaves distinctly stalked, elliptical or strapshaped- -elliptical ors 
shaped, with the midrib excurrent into a long soft spine; margins 0 
