174 



Essential Character. — Movers usually diclinous, moncecious, naked, with 2 fistular 

 coloured bractese. Stamens single ; filament filiform, furrowed along the middle; anther 

 reniform, 1-celled, 2-valved; the valves opening fore and aft. Ovarium solitary, 4-cornered, 

 4-celled ; otmles solitary, peltate ; styles 2, right and left, subulate ; stigmas simple points. 

 Fruit 4-celled, 4 seeded, indehiscent. Seeds peltate ; embryo inverted in the axis of fleshy 

 albumen; radicle very long, curved, superior; cotyledons very short. — Small aquatic herba- 

 ceous plants, with opposite, simple, entire leaves. Flowers axillary, solitary, very minute. 



Affinities. I have remarked in my Synopsis, that " the affinity of this 

 order to other dicotyledons appears to be of precisely the same nature as that 

 borne by Lemna to monocotyledons : they each exhibit the lowest degree of 

 organization known in their respective classes." Mr. Brown considers it allied 

 to Halorageae ; an opinion in which I concur, without adopting Decandolle's 

 explanation of the structure of the flowers ; but at the same time I confess 

 that this affinity is less strong than could be wished ; is it not rather an ano- 

 malous form of a reduced Euphorbiacea, or is it related to Podostemese 1 All 

 this is still a problem. 



Geography. Natives of still waters in Europe and North America. 



Properties. Unknown. 



Examples. Callitriche. 



CLXV. CERATOPHYLLE^E. 



CERATOPHYLLEa:, Dec. Prodr. 3. 73. (1828) ; Lindl. Synops. 225. (1829.) 



Diagnosis. Apetalous dicotyledons, with definite pendulous ovula, solitary 

 flowers, a 1-celled ovarium, and many-parted calyx. 

 Anomalies. 



Essential Character. — Flowers monoecious. Calyx inferior, many-parted. Stamens 

 from 12 to 20 ; filaments wanting; anthers 2-celled. Ovarium, superior, 1-celled ; ovule 

 solitary, pendulous ; stigma filiform, oblique, sessile. Nut 1 celled, 1-seeded, indehiscent, 

 terminated by the hardened stigma. Seed pendulous, solitary ; albumen ; embryo with 4 

 cotyledons, alternately smaller ; plumula many-leaved ; radicle superior. (Dec.) — Floating 

 herbs, with multifid cellular leaves. 



Affinities. These are not at all made out. In consequence of the num- 

 ber of its cotyledons, Richard placed it near Coniferre, with which it seems to 

 have no kind of affinity. Decandolle urges its relation to Hippuris and Myrio- 

 phyllum, among Haloragea; from which it differs in its superior ovarium j and 

 he inquires whether Naias, which according to some is dicotyledonous, does 

 not belong to the same order. Can this family have any relation to Podoste- 

 meae ? Agardh places it among Fluviales. 



Geography. Found in ditches in Europe. 



Properties. Unknown. 



Example. Ceratophyllum. 



