NAIADACEiE. 53 



SnB-SpEciEs (?) I.— Potamogeton flabellatus. Bah. 



Plate MCCCCXXI. 



ndch. Ic. n. Germ, et Helv. Vol. VII. Tab. XIX. Fig. 31. 

 Lah. Man. Brit. Bot. ed. vi. p. 366, and Phytol. Vol. IV. p. 1158. 

 P. zosteraceus, Bah. Man. Brit. Bot. ed. i. p. 325 (non Fries), 

 P. pectinatus, var. /3, Hooh. & Am. Brit. Fl. ed. viii. p. 479. 

 P. pectinatus, " var. dicliotomus, Wallr." Reich. 1. c. p. 12. 

 "P. VaiUantii, Bom. & Schidtes." Teste Eeich. 1. o. 



Leaves flat; the earlier ones broadly linear, 3- to 5-rlbbed; upper 

 leaves narrowly linear, 1- to 3-ribbed. Nuts nearly straight on the 

 upper margin, with the lateral keels indistinct ; the central keel 

 prominent. 



In rivers, ditches, and canals, in fresh and brackish (?) water. Appa- 

 rently not uncommon in England, extending north to Lancashire and 

 Yorkshire, but the plant is so confounded with the following sub- 

 species that it is impossible at present to give its exact distribution. 

 Li Ireland it is found near Cork, Fermoy, Clonmel, and near Straffan, 

 KUdare. 



England, Ireland. Perennial. Summer. 



Rootstock creeping, springing from a small tuber. Early leaves 

 3 to 8 inches long, and |^ to |^ inch wide ; these leaves, however, are 

 mostly decayed by the time the plant comes into flower, and the upper 

 leaves are not more than yV inch broad, and often narrower. Flowers 

 in 4 to 8 whorls, mostly 2 in a whorl. Peduncles (exclusive of the 

 spike) 1 to 4 inches long ; the spike itself 1 to 2 inches. Nuts ^ inch 

 long. The stipules, adhering to the leaf-stalks and forming a basal 

 sheath, distinguish this plant, when not in flower, from aU those of the 

 preceding sections. 



The Rev. Kirby Trimmer, in the " Flora of Norfolk," states that iu 

 the Trent, by AValton-on-Trent bridge (Derby), he has "always met 

 ■with plenty of the broad lower leaves in undecayed condition thi'ough 

 the months of July and August." 



Fan-like Pondweed 



SnB-SpEciEs (?) II.— Potamogeton eu-pectinatus. 



Plates MCCCCXXII. MCCCCXXm. 



Billot, Fl. Gall, et Gorm. Exsicc. No. 3250. 



P. pectinatus, Bab. Man. Brit. Bot. ed. vi. p. 366. 



P. pectinatus, var. a. Hook. & Am. Brit. Fl. ed. viii. p. 479. 



Early leaves flat, linear, usually 3-ribbed; upper leaves setaceous, 

 1-ribbed, composed of 2 interrupted tubes. Nuts sliglitly convex on 



