564 OLXX. NAIADACE^E. (J. D. Hooker.) 



2. APONOQETON, Thumb. 



Submerged scapigerous plants ; rootstocks tuberous. Leaves floating or 

 erect, oblong. Scape long, bearing a single or twin sessile spikes of often 

 unilateral or distichous bisexual flowers ; the very young spikes enclosed 

 in a conical deciduous sheath. Perianth 0, or of 1-3 equal or unequal 

 white segments. Stamens 6 or more, filaments subulate, unequal, persis- 

 tent ; anthers didymous. Carpels 3-6, 2- or more- ovuled ; style short, stigma 

 discoid or decurrent p ersistent ; ovules basilar, anatropous. Fruii of 3 or 

 more coriaceous follicles. Seeds erect; embryo straight. Species about 

 20, Asiatic, African and Australian. 



1. A. monostachyon, Linn. f. Suppl. 214 ; leaves floating oblong 

 3-5-nerved opaque, cross nervules distinct, spike solitary, sepals 2 shorter 

 than the 3 smooth 4-8-seeded follicles. Roxb. Cor. PI. i. 58, t. 81 ; Fl. Ind. 

 ii. 210; Thw. Enum.%23; Dalz. & Gibs. Bomb. FL 248; Griff. Notul. iii. 

 203 ; Wall. Cat. 5167, A, B, C, E. ; Andr. Bot. Rep. vi. t. 406. A. mono- 

 stachys, Edgew. in Hook. Lond. Journ. Bot. iii. (1844), 405, 1. 17. A. luceiis, 

 Herb. Madr. A. flavidum, Herb. Ham. Spathium monostachyum, Edgew. 

 in Calc. Journ. Nat. Hist. iii. (1843), 533, 1. 16. Potamogeton indicus, 

 Roth ex Roem. Sf Sen. Syst. iii. 576. Saururus natans, Linn. Mant. 227. 

 Rheede Hort. Hal. ii. t. 15. 



Tanks, &c., throughout INDIA and CEYLON. DISTEIB. Trop. Asia ami 

 Australia. 



Leaves 3-6 in., acute or obtuse, herbaceous, base cuneate rounded or cordatf. 

 Spike 1-6 in., lax or dense-fld. Sepals obovate to lanceolate. Stamens 6. Seeds 

 oblong. Submerged leaves membranous transparent and with distinct cross- 

 nervules as in A. crispum. 



2. A. crispum, Thunb. Nov. Gen. i. 73; leaves submerged from 

 linear-oblong to lanceolate 3-7-nerved membranous translucent cross- 

 nervules distinct, spike solitary, sepals much longer than the 3-4 smooth 

 1-2-seeded follicles. Thw. Enum. 333. A. undulatum, Roxb. Fl. Ind. ii. 

 211 ; Wall. Cat. 5167, D. 5168 ; 5175, F. ; Aitchis. Cat. Panjab PI. 145. 

 Ouvirandra undulata, Edgew. in HooJc. Lond. Journ. Bot. iii. (1844), 405, 

 t. 18. Spathium undulatum, Edgew. in Calc. Journ. Nat. Hist. iii. (1843), 

 533, t. 15. Limogeton, Edgew. ex Griff. Notul. iii. 203. 



Tanks throughout INDIA and CEYLON. DISTRIB. Australia. 



Leaves 1-3 ft., flat or undulate ; base acute rounded or cordate. Sepals very 

 variable in size, if two species be not confounded under this name. Roxburgh 

 describes them "as in mono st achy on," but in some specimens they are fully | in. 

 long. 



3. A. echinatum, Roxb. Fl. Ind. ii. 210 ; leaves floating linear - 

 oblong 3-5-nerved opaque cross-nervules obsolete, spike solitary, sepals 

 shorter than the 3 echinate 2-seeded follicles. 



Tanks in BENGAL, Roxburgh. 



I have seen but one specimen of what I take to he this plant, in Herb. Wight, 

 named A. dispermum. Wight says it quite resembles A. monostachyon, except in the 

 follicles, which are larger, 2-seeded, more narrowed into a nearly straight beak, and 

 they are dorsally irregularly ridged. Roxburgh describes ccMnatum as about 

 6-seeded ; hut he figures on the plate of A. monostacliyon, apart from the enlarged 

 6-seeded follicles of that plant, 3 others carpels which are strongly echinate and 

 2-seeded, and to which he doubtless alludes under his description of the former, 



