94. POTAMOeEIOKACEi. 3fil 



cal and spongy beneath, roots solitSiy blunt. — E. £. 1233. H. 

 vii. 14. Tehnaiophace ScMeid., Endl. — Fronds 1 — 2 lines long, 

 at first flattiah, afterwards . remarkablv jribbous and cellular 

 beneath.— On stagnant water. A. \1. VIIL E. S. I, 



4. X. polyrrhiza (L.) ; fronds roundish-obovate, compressed, 

 roots many clustered acute. — E. B. 2458. R. vii. 15. Spirodda 

 Schleid., Endl. — ^Fronds half an in. long, green above, purple 

 beneath, Fl. have not been seen in Britain. — On water. A. 



E. S. I. 



** Fronds with only 1 frondbesaring chink ; no roots. FL from 

 "centre of upper surftice. — Wolffia Hork. 



5. L. wrhisa (L.) ; fronds verif small subglobtdar flattish 

 above solitary, YOiing frond sepai-ating immediately from the 

 old one. — M. ^ii. 14 — Frond not ^ the size of those oiL. minor, 

 subglobular at all ages, green. Bud from within the base of the 

 old fiond. — Ponds near London. A. E. 



Order XCIV. POTAirOUETOXACEJE. 



Fl. perfect or imperfect. Perianth inferior, 4-parted, or 0. 

 Stam. free, 1, 2 or 4. t Ovaries 4, distinct, each with 1 ovule 

 and 1 sessile stigma. Fr. a drupe enclosing^a hard nut, or a dry 

 nut, not bursting, 1-seeded. Albumen 0. Embryo with a thin 

 skin having a lateral cleft. 



1. PoTAStOGETON. Fl. perfect. Perianth 4-parted. Anth. 

 4, sessile, opposite to the divisions of the perianth. Ovaries 



' 4. Styles 0. Drupes 4, sessile. — ^FL sessile, spiked. 



2. EuppiA. Fl. perfect Perianth 0. Stam. 2, the cells 

 considerably separated ; filaments very short, scalelike, y 

 Ovaries 4. Styles 0. Nuta 4, with long stalks. — ^Fl. about 

 2 together. 



3. ZAyyiCHT-.TXiA. Fl. monoecious, axillary. Barren with 1 

 stam., and no perianth. Fertile with a beUshaped perianth, 

 persistent style, and peltate stigma. Xuts 3—5 or more, 

 more or less stalked. 



1. PoTASioeB'iox Linn. PondweeJ. 



* L. dtieniate,Jloriil l. floating and sometimes opposite ; stipules 

 free. 



1. jR -adtatis (L."); 1. all stalked, upper coriaceous floating 

 ovate or elliptic folded at the base, lower leafless petioles^ linear 

 or setaceous, fr. (large) roiatded on the back when fresh keeled 



