130. NAIADACE.E. 2. Potamogeton. 



:2. A. crispum, Tkunb. Syn. A. undulatum, Roxb. 



Rootstock stoloniferous. Leaves submerged (or floating, JRoxb.) 

 lanceolate to linear-oblong, 4-6" long, under 1" broad, 3-7-nerved 

 with compressed petioles. Cross nervules very fine and numerous. 

 Scape thickening upwards, spike solitary, 1-0-3-5" long. Flowers 

 crowded white. Tepals up to -3" long, very variable in size (F.B.L). 

 Follicles shoitei than the tepals, 3-4, smooth, 1-2-seeded. 



Extends from the United Provinces and Central Provinces to Lower Bengal, and 

 -therefore almost certainly to be found in our area, Fl. r.s. 



The F.B.I, states that the leaves are 1-3 ft. long. Some Madras specimens have 

 leaves 1-1" by 1*1", but these are the largest I have seen. The spikes just raise 

 themselves above the water. Stamens lilac. The rootstock is edible. 



2. POTAMOGETON, L. 



Aquatics with a creeping rootstock, elongate submerged stem and 

 submerged or floating, opposite or alternate, entire mere rarely 

 toothed, leaves and intrapetiolar stipules. Flowers greenish, spicate 

 on a lateral peduncle rising above the surface of the water from a 

 membranous spathe or sheath, ebracteate, 4-mercus throughout. 

 Sepals 4 concave, green, valvate. Anthers sessile on the sepals (or 

 according to some authors the so-called sepals are merely scales 

 developed at the back of the anthers) didjmious, with a cell each side 

 of the claw, extrorse. Carpels 4 sessile, 1 -celled, 1-ovuled with sub- 

 ■sessile or decurrent persistent stigma. Ovule inserted in the inner 

 angle, camplotropous. Fruit of 4 coriaceous or spongy drupels with 

 reniform seeds. 



I. Leaves, at least the upper, floating, oblong or elliptic : — 



Floating leaves coriaceous 3-4" long, submerged lanceolate 1. l adieus. 

 Floating leaves •5-l'o" long, submerged linear or filiform . . 2. javanicus. 

 IT. Leaves all submerged, oblong lanceolate or linear (exc. jyer- 

 foliafus): — 



A. Leaves ovate, cordate, amplexicaul perfoliatug 



B. Leaves lanceolate or oblong: — (p. 8-48). 

 L. subamplexicaul, 3-nerveil, crisped and serrulate . . 3, o'ispiis. 



L. neither amplexicaul nor crisped, 3- or more-nerved . . 4. mucronatut. 



C. Leaves narrowly linear or filiform : — 



L. 1-3-nerved. Stipules adnate to leaf-sheath . . . o. pecfinatia. 

 L. 3-5-nerved. Stipules small, free 6. pu^illui. 



1. P. indicus, Roxb. Indian Pond- weed. 



Stem slender terete, branched. Leaves nearly all floating in shallow 

 water, upper ones only in deep water, elliptic or oblong or elliptic- 

 lanceolate 2 -.5-4" hy 1-1-75", rounded obtuse or acute both ends, 

 rather coriaceous, shining with strong midi'ib and many moie slender 

 parallel nerves mostly proceeding fi'om near the bate, petioles 1-4", 

 stipules free 1-1-5"; submerged leaves lanceolate, undulate, mem- 

 branous and often elongate (up to 8", Cooke), f)etioles shorter. Spike 

 -7-1-5" long on axillary or leaf-opposed peduncles Avhich raise it just 

 above the water. Flowers densely packed Avithout spaces between 

 the whorls. Sepals (or scales of anther ?) -1" long including the long 

 claw, limb suborbicular concave about -08" diam. Drupels -12" long, 

 obliquely truncate, shortly beaked. 



847 



