| 
42 ENGLISH BOTANY. 
but often there are leafy branches in place of the axillary peduncles, | 
Fruiting-spike 1 to 2 inches long, consequently shorter than that of © 
P. lucens, but much thicker. Nuts larger than in any of the other 
British species, nearly } inch long, by } inch deep, keeled when dry, 
Prof. Babington states that when fresh they are rounded, and rarely 
keeled on the back; but a large number of specimens sent me from 
Rockland Broad, Norfolk, by the Rev. Kirby Trimmer, had the fresh 
fruit furnished with a very acute keel, and the Rev. W. W. Newbould 
informs me that this is also the case in the plant found at Oxford. 
The plant from the Waveney at Bungay, collected by Professor 
Babington, has the dried fruit smaller than that from Norfolk, more com- 
pressed, with a fainter central, and much more prominent lateral keels, 
in this agreeing with the plant from Loch Lee, Nairn, and Guthrie 
Burn, Forfar, from both of which stations I have specimens in fruit. — 
Long-stalked Pondweed. 
French, Potamot flerueuz. German, Gestrecktes Samkraut. 
SPECIES XUIL—POTAMOGETON PERFOLIATUS. Linn 
Pirate MCCCCXII. 
Reich. Ic. Fl. Germ. et Helv. Vol. VII. Tab. XXIX. Fig. 53. 
Stems slender, sparingly branched, the lower branches barren, the 
upper branching more or less dichotomous. Leaves all similar, the lower 
ones alternate, the uppermost and those at the base of the forks of the 
stem opposite, submerged, sessile and amplexicaul, spreading-ascending, 
flat, ovate or oblong-lanceolate, cordate at the base, obtuse or subacute, 
not apiculate nor cuspidate nor hooded at the apex, not serrate at the 
margin, with 5 to 7 strong ribs and several fainter intermediate ones 
connected by rather distant transverse veins, and with narrow bands of 
very elongate cancellate areolation at the sides of the ribs. Stipules 
small, usually absent or evanescent, except in the uppermost leaves and. 
those at the forks of the stem, and often present only in the latter 
case and in those leaves which have peduncles in their axils, subacute, 
scarious, with a few distant slender fibres. Peduncles terminal be- 
tween the forks of the stem and axillary, rather short, slender, equal 
in thickness. Sepals with their lamina suborbicular. Fruiting-spike 
rather dense, shortly oblong-cylindrical, rather few-flowered. Nuts 
olive, rather large, not acuminated and but slightly compressed, curved 
along the upper margin, semicircular and very bluntly keeled on the 
back, terminated by a very short central beak. Plant bright green, 
turning olive and sometimes black and dim in drying. , 
In ditches, slow streams, and lakes. Rather common, and generally 
distributed, extending north to Orkney. 
