478 



CV. NAIADACE^E. 



lPofamogeto7i. 



4. L. gibha L. (gibbous D.) ; fronds obovate nearly p]a^,. 

 above, hemispherical beneath.- JS, B. t. 1233. "^ ' ^ i ' ^le 

 iSch le id. 



Tclmatophace 



1 



Stagnant water, bnt not very frequent. Rare in Scotland. q 

 6 — 9. — Size of L, minor, but readily distinguished by its gibbous o 

 even hemispherical lower surface, which is, moreover, white, pellucl/ 

 and beautifully cellular, upper side plane, green, opaque. Stameyu 2 

 Ovarij with 2—7 erect ovules. Utricle at length bursting transversely* 

 Seeds usually 2—4, rarely more, or solitary, erect. 



Orb. CV. NAIADACEiE Juss. 



riowers perfect i and all sessile, or imperfect and monoecious 

 or dioecious. Perianth ^ of the perfect fi. of 3 

 shaped or clawed scales, or wanting ; of the imperfect ones 

 usually wanting, sometimes of 1—2 "scales. 



4 wedire- 



bypojTcynous. 



Stamens definite, 

 Ovaries solitary or several, 1 -celled. Ovules 

 usually solitary, erect or pendulous, rarely 3 and erect. Style 

 simple, or more or less deeply 2— 3-cleft. Pericarps dry, inde- 

 hiscent, i-celled, ^1- (or rarely 2-) seeded. Embryo without 

 albumen, with a thin skin, havino; a lateral cleft for the emission 

 of the plumule. Radicle next the hilum^ or at the opposite ex- 

 tremity of the seed. — Sub me?^ged or floating aquatics, with 

 very cellular leaves and stems. Flowers inconspicuous, sometimes 

 xspiked, 



1. PoTA:\roGETo:!T. riowcrs perfect. Perianth of 4 unguiculate sepals. 



Stamens 4. Carpels 4, sessile, ' Style entire. 



2. RurpiA. Flowers perfect. Perianth 0. Stamens 4. Carpels 4, oa 



long stalks. Stigma sessile, entire. 



3. Zanxichellta. Flowers imperfect, axillary. Carpels 4 or more, 



sessile. Style elongated, entire. Stigma discoid. 



4. Najas. Flov/ers imperfect, axillary, solitary. Carpels solitary, sessile. 



Style witk 2—4 elongated stigmas. 



5. ZosTERA. Flowers imperfect, arranged on a ilat spadix within a 



foliaceous spatha. Carpels sessile. Style with 2 elongated stigmas. 



* Pollen globose or oblong. Plants groivlng in fresh water, 



rarely in salt-marshes. 



L PoTAMOGETOK Limu Pond- weed. 

 Flotcers perfect, sessile, upon a spile (or spadix?) which 



1 We would gladly have adopted the opinion of Dr. Lindley by limiting this 

 Order to those genera which had imperfect flowers ; but we can scarcely remove 

 Iluppm, Potanlogeton, Apunogeton, and Ouviranda to the Suncaeinacea: . KccorA- 

 Jng, hovvever, to the views of Decaisne, Kmith, and some oarers, the supposed 

 sepals of these genera are merely bracteas, each stamen and carpel being a.distinct 

 flower; so that these plants have really all imperfect flowers, and are properly 

 Rlaced here, fhe perianth, if Mich it be, is sessile, on a kind of spadix or thickish 

 peduncle: in the true Juncagmaceo! the lower flowers at least are stalked, pre- 

 venting any ambiguity about the perianth or their being truly perfect. 



ales' 



f 



(If. 



a. 



0ter. 



1 



t 



ijte, slit 



\ 



I 



$1 



Ditches, 



small rouii 

 liiDjitiitlin;] 



(3cli side, t 



%% 



i I pe 



[mm or 



stij 



slai 

 ' (m obs( 

 Am w 



j'' fflariiius 



l-nervedj i 



, ^'«us tar. 



