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MONOECIA POLYANDRIA. 

 437. CERATOPHYLLUM. Hornwort. 



Zi/m. Gen. 4 93. Juss. 18. Fl. Br. 1020. Lam.t.775. Gcertn. t.44. 

 Dichotophyllon. Dill. Gen. 9\.i.3. 



Nat. Ord. Inundatce. Linn. 15. Naiades. Juss. 6. Rather 

 akin to Hippuris; see v. 1. 4; and therefore to Mr. 

 Brown's HaloragecE ; see Grammar^ 167. 



Barr.Jl. Cal. in many, deep, equal, oblong, permanent, up- 

 right segments. Cor. none. Filani. twice as many as 

 the segments of the calyx, 16 — 20, erect, very short. 

 Antli. oblong, erect, rising above the calyx. 



Fert.Jl. Cal. as in the barren fl. Coi: none. Germ, superior, 

 ovate, compressed. Style scarcely any. Stigma simple, 

 oblong, oblique. Driipa ovate, compressed, crowned 

 with the permanent stigma ; its coat thin. Nut large, so- 

 litary, the shape of the drupa ; with 2 obovate cotyledons ; 

 and a many-cleft central embryo. 



Branched floating lierhs., with whorled forked leaves^ and 

 axillary, sessile^^owers. 



This genus is supposed by some botanists to be monocoty- 

 ledonous, though Jussieu suspected otherwise, and Gaert- 

 ner has plainly shown it to have 2 very distinct cotyle- 

 dons., which he chose to call a vitellus, taking the many- 

 cleft embryo, or pliimula, for cotyledons. The appearance 

 of this latter part seems to have led M. Richard to think 

 the genus allied to the Conifei-ce ; but if it had really 

 many-cleft cotyledons, like Pinus, that circumstance 

 would only prove such a character worthless, as to real 

 natural affinity. See Lindley in HooJc. Scot. p. 2. 297. 



1. C. demersum. Common Hornwort. 



Fruit armed with three spines. Segments of the calyx 

 notched at the extremity. 



C. demersum. Linn. Sp. PLXAOd. Willd. v. 4.405. Fl.Br. 1020. 



Engl. Bot. V. 14. t. 947. Hook. Scot. 2/2. Gartn. v. 1. 212. 



t.44; lastf. 

 C. n. 1599. Hall. Hiit. v. 2. 275. 

 Dichotophyllon. Dill. Giss. 149. 

 Hydroceratophyllon folio aspero, quatuor cornibus armato. Vaill. 



Mem. lie VAc. des Sc. 299. 1. 15./. 1 . Raii Syn. 135. 



