46 ENGLISH BOTANY. 
Leaves all similar, sessile and semiamplexicaul, broadly linear, broad — 
at the base, acuminate-cuspidate, translucent, with 3 (rarely 5) strong 
ribs, and numerous faint ones between them. Stipules large, acute, 
pellucid, scarious, with numerous slender longitudinal fibres. Pe- 
duncles terminal between the forks of the stem, and sometimes pseudo- | 
axillary,* longer than the spike, and often twice as long, rather stout, 
slightly thickened upwards. Sepals with their lamina suborbicular, 
Fruiting-spike oblong or cylindrical-oblong, dense, many-flowered. 
Fruit olive, rather large, very slightly compressed, not acuminated, 
convex on the upper margin, on which there is a slight boss, but no 
tooth near the base, nearly semicircular, and bluntly 3-keeled on the 
back, terminated by a short central beak. Plant bright green or olive- 
green, retaining its colour when dried. 
In ditches, slow streams, and lakes. Rather rare. I have seen 
specimens from Essex, Middlesex, Cambridge, Warwick, Stafford, — 
Leicester, Norfolk, Derby, and Forfar, and it is reported from Fife, and 
to have been formerly seen in a rivulet at Nottingham, and at Hoving- 
ham in Yorkshire. In Ireland it is very rare, and has been found 
only in County Down. 
England, Scotland, Ireland. 
Stems remarkably flattened, } to } inch broad. Leaves 3 to 6 
inches long, 4} to 4 inch broad, rather suddenly contracted into a 
cuspidate point; peduncles, exclusive of the spike, 1} to 3 inches 
long. Spike } to 1 inch long, with numerous flowers. Fruit } inch 
long. 
Grass wrack-leaved Pondweed. 
German, Flachsstengeliges Samkraut, 
SPECIES XVIIL—POTAMOGETON ACUTIFOLIUS. Link. 
Pirate MCCCCXVI: 
Reich. Ic. F1. Germ, et Helv. Vol. VII. Tab. XXVI. Fig. 44. 
Billot, F). Gall. et Germ. Exsicc. No. 1067. 
Stem flattened, broad, and subfoliaceous, repeatedly dichotomous. — 
Leaves all similar, sessile and semiamplexicaul, linear, broad at the 
base, acuminate-acute, translucent, with 3 strong ribs and numerous 
faint ones between them. Stipules rather large, acute, scarious, with 
numerous rather strong longitudinal fibres. Peduncles terminal be-— 
* No doubt where they appear to be axillary, it arises from one of the two branches 
only being developed. 
