ENnLISII ROTANT. 



bnse, obtuso, subapiculntc, tranBlncent, with 3 (rarely 5) strong ribs, 

 without I'aint ones between them. Stipules rather small, subacute, 

 scarious, with numerous slender longitudinal fibres. Peduncles ter- 

 minal between the forks of the stem, equalling or slightly exceeding 

 the spike, rather slender, not thickened upwards. Sepals with their 

 lamina deltoid-rhombic. Pistils 4. Fruiting-spike oblong-ovoid, dense, 

 rather few-flowered. Fruit moderately large, brownish-olive, slightly 

 compressed, not acuminated, convex on the upper margin, on which 

 there is no tooth, semicircular and 3-keeled on the back, terminated by 

 a very short central straight beak. Plant rather dark green, sometimes 

 tino-ed with red, retainmg its colour when dried. 



In ditches and ponds. Rather scarce, but widely distributed. I 

 have seen specimens fi'om the counties of Sussex, Kent, Surrey, 

 Hereford, Warwick, Salop, Chester, Lancaster, and Kincardine, and 

 there is o-ood authority for extending its range south-west to Dorset 

 and Devon. Rare, and local in Ireland, where it occurs both in the 

 south and north, but has not been observed in the midland counties. 



England, Scotland, Ireland. Perennial. Summer. 



Usually a smaller and more branched plant than the two preceding 

 species, and differing greatly in its slender stem, which is scarcely 

 flattened, and in the absence of faint intermediate ribs in the leaves, 

 which are also distinctly narrowed towards the base. The leaves arc 

 2 to 3 inches long by |^ to ^ inch broad, and are not acuminated into 

 an acute point at the apex, where the margins meet in the form of a 

 wide o-othic arch. Peduncles, exclusive of the spike, ^ to f inch long. 

 Spike about i uich long. Nuts l inch long, in form resembling those 

 of P. zosterifolius, but more convex on the upper or inner margin. 



This is a well-marked species, which only a superficial examination 

 could confound with either of the two preceding species. I have never 

 seen more than 3 ribs on the leaves of this plant, but Koch says they 

 are 3- to 5-nerved. 



Grassy Pondweed. 



French, Potamot afeuilhs ohf.nsa:. German, Stumpfhlallrujcs Samh-aut 



SPECIES (?) XIX.— POTAMOGETON MUCRONATUS. Schrad. 

 Plate MCCCCXVm. 



Eeich. Ic. Fl. Germ, et Helv. Vol. VII. Tab. XXIV. Fig. 42. 



P. compressus, Sm. Engl. Bot. ed. i. No. 418. Engl. Fl. Vol. I. p. 233. Bah. Man. 



Brit. Bot. ed. vi. p. 365. Eeich. I.e. p. 15. 

 P. pusillus, var. major, Fries. Nov. Fl. Suec, p. 48, and Summ. Veg. Scand. p. GO 



(68). Book. & Am. Brit. Fl. ed. viii. p. 480. 

 P. Oederi, " Meyer," Boreau, Fl. du Centr. de la Fr. ed. iii. Vol. II. p. 601. 



Stem 4-sided, considerably compressed, slender, not foliaceous, 



