46 KyOLISTl BOTAinr. 



Leaves all similar, sessile and semiamplexicaul, broadly linear, hroad 

 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- 

 axillar)',* longer than the spike, and often twice as long, rather stout, 

 slightly thickened upAvards. Sepals with their lamina suborbicular. 

 Fruiting-spike oblong or cylmdrical-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-keelcd on the 

 back, terminated by a short central beak. Plant bright green or olive- 

 gi'een, 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 Do\vn. 



England, Scotland, Ireland. 



Stems remarkably flattened, |- to :^ inch broad. Leaves 3 to 6 

 inches long, ^ to ^ inch broad, rather suddenly contracted into a 

 cuspidate point; peduncles, exclusive of the spike, 1^ to 3 inches 

 long. Spike f to 1 inch long, with numerous flowers. Fruit ^ inch 

 long. 



Grass tcrack-leaved Pondweed. 



German, Flaclisstengeliges SamhrauU 



SPECIES XVn.-POTAMOGETON ACUTIFOLIUS. Linh 



Plate MCCCCXVI. 



Bnkh. Ic. Fl. Germ, et Hely. Vol. VU. Tab. XXVI. Fig. 44. 

 Billot, Fl. Gall, et Gei-m. Exsicc. No. 10G7. 



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 bc- 



* No doubt where they appear to be axillary, it arises from one of the two branches 

 only being developed. 



