CXLIV. NAIADACB^. 837 



1. Aponogeton monostachyon, Limi. f. Suppl. (1781) p. 214. 

 An aquatic herb ; rootstock i-i in. iu diam., stoloniferous, edible. 

 Leaves floating, 2|-8 by 5-II in., oblong or linear-oblong, acute or 

 obtuse, base cuneate, rounded, or cordate, 3-5-nerved and with 

 numerous distinct cross nervules between them ; petioles varying with 

 the depth of the water, often very long, subtrigonous. Scape varying 

 with the depth of the water ; spike solitary, i-6 in. long, dense- or 

 lax-flowered ; flowers white, pink or pale blue. Sepals 2, obovate 

 or suborbicular, -^ in. long and broad. Stamens 6, as long as or 

 longer than the perianth-segments ; anthers bluish-purple. Carpels 3. 

 Follicles subglobose ; style subulate. Seeds 4-8, oblong ; testa lax, 

 6-8-ribbed. striate. Fl.B. I. v. 6, p. 564 ; Grah. Cat. p. 200 ; Dalz. & 

 Gibs. p. 248 ; Trim. PI. Ceyl. v. 4, p. 372 ; Woodr. in Journ. Bomb. 

 Nat. V. 13 (1901) p. 429 ; Prain, Beng. Pi. p. 1122 ; Watt, Diet. Econ. 

 Prod. V. 1, p. 277. — Plovv^rs : July-Dec. 



KoNKAN : Stocks !, Graham ; Salsette, Graham. S. M. Country : tanks in the 

 Dharwar and Belgaum Oollectorates, Balzell ^ Gibson ; Saraasji (Dharwar districta), 

 Woodrow ! Gujarat : Godra, Woodrow. — Distrib. Throughout India ; Ceylon, 

 Tropical Asia, and Australia. 



2. POTAMOGETON, Linn. 



Aquatic submerged herbs with creeping rootstock. Leaves submerged 

 or floating, opposite or alternate, entire or toothed ; stipules inter- 

 foliaceous. Plowers minute, hermaphrodite, spicate on a short or long 

 axillary or leaf-opposed peduncle arising from a sheath ; bracts 0. 

 Perianth of 4 concave green valvate segments. Stamens 4 ; anthers 

 sessile at the base of the segments of the perianth, didymous. Carpels 

 4, free, sessile, 1-celled and 1-ovulate ; ovule campylotropous, adnate 

 to the inner angle of the carpel ; stigma subsessile or decurrent, 

 persistent. Pruit of small coriaceous or spongy drupelets. Seed 

 subreniform ; embryo macropodal. — Disteib. Species about 80, cosmo- 

 politan. 



Upper or all leaves floating 1. P. indiciis. 



Leaves all submerged. 



Leaves amplexicaul, ovate, cordate, entire, translucent, 

 5-9-nerved ; stem stout ; peduncle short ; spike dense- 

 flowered 2. 'P.perfoUatus. 



Leaves semiamplexicaul, linear-oblong, crisped, serrulate, 

 translucent, 3-nerved ; stem slender ; peduncle long ; spike 

 fevF-flo wered 3. P. crisfus. 



Leaves filiform, opaque ; stem filiform ; flowers in distant 



whorls on the peduncle 4. P. pectinatus. 



1. Potamogeton indicus, lioxh. Fl. Ind. v. 1 (1832) p. 452. Stem 

 terete, branched, smooth, its length depending on the depth of the 

 water. Leaves petiolate ; the upper floating, 2^-4 by 1-1 1 in., alternate 

 or uppermost opposite, oblong or elliptic-lanceolate, acute, obtuse or 

 acuminate, thinly coriaceous, opaque, glossy, many-uerved, base acute or 

 rounded, the petioles variable iu length with stipules 1-1 j in. long, 

 free ; the lower submerged leaves reaching 8 in. long, membranous, 

 undulate, with petioles shorter than the blade. Peduncles axillary or 

 leaf-opposed, 1-2 iu. long, stout or slender, not thickened upwards. 

 Spike 1| in. long, dense-flowered, green. Sepals 4, clawed, ^ in. long, 



