568 CLxx. NAiADAOB^. (J. D. Hooker.) 



4. RUPFXA, Linn. 



Submerged slender branched brackish-water plants. Leaves elongate, 

 filiform, sheaths stipuliform. Flowers minnte, bisexnal, 2-6 together within 

 the leaf-sheath on a short peduncle which usually elongates greatly after 

 flowering, and is then straight or spirally twisted. Perianth 0. Anthers 

 2, sessile, opposite, 2-oelled. Oa/rpels 4, 1-ovuled, at length (in fruit) long-, 

 stipitate, stigma sessile ; ovule pendulous. Achenes ovoid, obtuse or 

 beaked. Seed uncinate, embryo macropodal. — Species temperate and sub- 

 tropical. 



R. rostellata^ Koch in Beichh. Ic. Crit. ii. 66, fig. 306 ; lo. Fl. Germ. 

 vii. t. 25; peduncle straight after flowering, achenes obliquely ovoid acutely 

 beaked. Boiss. Fl. Orient, v. 20. E. maritima, QHf. Notul. iii. 196 ; Ic. 

 PI. Asiat. t. 257-259. 



THBOTiaHOUT India and in Ceylon, in brackish water. — Disteib. Europe temp, 

 and trop. Asia. 



Stem 2 ft. and upwards. Leaves 1-3 in. Fruiting peduncle 1-6 in. Achenes 

 ■^ in. long. 



5. ZANNICHEIiIiXA., Linn. 



Submerged salt-water plants, with slender rootstock and stems. Leaves 

 linear, sheaths stipular. Flowers minute, enclosed in the leaf-sheaths, a 

 male and fern, in one membranous spathe. Male fl. a linear 2-3-ceUed 

 anther, filament slender. Fem. fl. perianth cupular hyahne. Carpels 

 2-9, sessile; style long slender, stigma oblique peltate crenate.; ovule 

 solitary, pendulous, orthotropous. Achenes 4, sessile or stipitate, reniform, 

 created. Seed pendulous, testa thin ; embryo subcylindric, cotyledonary 

 end twice folded on itself. — Species 4-5, or forms of one. 



Z. palustris, Linn. ^. PI. 969; suhsp. pbdicellata; male peduncle 

 short, achenes 2-4 subsessile, back crenate or tubercled, style as long as 

 the body of the achene or longer, anthers 2-celled. Aschers. Fl. Brandenb. 

 668 ; Boiss. Fl. Orient, v. 15 ; Micheli, Nov. Gen. t. 84, f . 2. Z. pedun- 

 oulata, Beichh. Fl. Germ. vii. t. 16 ; Ic. Grit. viii. t. 760. Z. gibberosa, 

 Beichh. 1. 1, c. c. t. 16 and t. 759. Ic. Fl. Germ. vii. t. 21, 22. Z. pedi- 

 cellata, Rwm. in Wall. Gat. 5185 ; Griff. Notul. iii. 190 ; Ic. PI. Asiat. t. 

 255, 256. 



Salt marshes and lagoons throughout India, ascends to 15,000 ft. in W. Tibet. — 

 DisiBiB. (of Z. palustris), all regions but ? Australia. 



I find the following forms amongst the Indian specimens : a, from Western Tibet ; 

 flowers sessile or very shortly pednncled, achenes stipitate, dorsally crenate, style 

 shorter than the achene ; h, from the Fanjab and Behar ; flowers sessile, achenes 

 stipitate smooth or tubercled dorsally or ventrally or both, style very long ; c, from 

 Western Tibet, alt. 12-13,000 ft. ; flowers sessile, achenes sessile very slender ; d, 

 from the Fanjab ; flowers subsessile, style as long as the achenes; e, from the Panjab 

 and Behar ; flowers peduncled, achenes small as long as their stalks, style shorter 

 than the achene. 



6. NAXAS, Linn. 



Submerged plants ; stem branched, filiform, smooth or muricate. Leav es 

 opposite alternate or whorled, linear, entire or toothed. Flowers minute, 

 axulary, monoecious or dioecious. Male pl. Perianth an outer tubular 

 or inflated entire or 4-fid tube and a hyaline inner. Stamen 1, adnat e 



