314 NAIADACEL. [ PoTAMOGETON. 
Fruit of 4 coriaceous or spongy drupelets, seed subreniform. 
Species about 85 with very numerous hybrids, cosmopolitan. 
Upper or all leaves floating. 
Floating leaves 3-4 inches long . - 1. P. indicus. 
Floating leaves 4-14 inches long é . 2. P. javanicus. 
Leaves all submerged. 
Leaves ovate, cordate, amplexicaul . . 3. P. perfoliatus. 
Leaves linear-oblong, semiamplexicaul, 
translucent 3-nerved . 3 7 . 4. P. crispus. 
Leaves filiform, opaque. ‘ . . 5. P. pectinatus. 
1. P. indicus, Roxb. Fl. Ind. J (1820) 452; F. B. I. vi, 565; 
Prain, Beng. Pl. 1123; Cooke Fl. Bomb. wi, 837. 
Stem terete. Leaves submerged up to 6 in. by 13 in. lanceolate, very 
thin, with about 7 nerves on either side of the midrib, acute, 
narrowed into a rather stout petiole about 1 in. long, floating 24-4 
by 1-12 in. oblong, elliptic or elliptic-lanceolate, rounded or acute 
at both ends, rather thick, opaque with many slender longitudinal 
nerves ; petioles 1-5 in. long, rather stout; stipules 1-14 in. long. 
Spikes 14-2 in. long, dense. Sepals >, in. long including the claw, 
limb suborbicular, concave. Drwpelets scarcely } in. long, oblique, 
shortly beaked, 3-ribbed on the back. 
Throughout the area, common, Dehra Dun, Agra, Merwara, Pilibhit, 
Kheri, Bahraich, etc. Flrs. Jan.-June. Distrrs.: Throughout India, 
Baluchistan, Ceylon, etc. 
2. P. javanicus, Hassk. in Act. Soc. Ind.-Needrl. I (1856) 26 ; 
F. B. I. vi, 566; Prain, Beng. Pl. 1123 ; Collett, Fl. Siml. fig. 179, 
Stems very slender. Leaves submerged very narrowly linear #5 in. 
wide, floating }-14 in. long, elliptic-oblong or elliptic-lanceolate, acute 
at both ends or subobtuse, 2-3-nerved on either side of the midrib; 
petiole about 4-4 in. long; stipules about 3-1 in. long. Spikes 
4-4 in. long, not very dense. Sepals + in. long, orbicular-obovate. 
Drupelets +5 in. long including the short slightly hooked beak (style), 
3-ribbed on the back, the ribs often denticulate. 
Dehra Dun (Mackinnon). Distriz.: Africa, S. & E. Asia, Australia. 
8. P. perfoliatus, Linn. Sp. Pl. (1753) 126; F. B. I. vt, 566 > 
Cooke Fl. Bomb. ii, 838. 
