Ceratophyllum.} CERATOPHYLLE/E. 239 



two bracteas) or none. Anther of one cell. Fertile fl. 

 Germen 4-lobed, lobes laterally compressed, indehiscent, with 

 four 1-seeded cells. Name ; icaXos, beautiful, and Opil- t hair. 

 Its stems are long and slender, and resemble hairs. 



Moncecia. Monandria. 



1. C. verna, Linn. Vernal Water Starwort. Fruit bearing 

 peduncles very short, with two bracteas at their base; fruit 

 regularly tetragonal, each portion bluntly keeled at the back. 

 Am. E. FL v. i. p. 10. Br. Fl. 1. p. 384. Am. in Ed. Journ. 

 of Nat. and Geogr. Sc. v. 1. p. 426. C. aquatica, E. Bot. t. 722. 

 Hook, in Fl. Lond. N. S. t. 127. 



Ditches, pools and slow streams, abundant. Fl. April, May. 0. 

 This varies much, as do almost all aquatic plants, in its foliage. Leaves 

 invariably connate. ( W. Wilson.) Upper and floating ones generally 

 oval and stalked, 3-ribbed ; lower ones single-ribbed, linear ; rarely all 

 linear. (Hooker.) 



2. C. autumnalis, Linn. Autumnal Water Starwort. Fruit- 

 bearing peduncles very short, without bracteas ; fruit irregularly 

 tetragonal, each portion broadly and acutely winged at the back. 

 Arn. E. Fl. v. i. p. 10. Br. FL 1. p. 384. E. Bot. Suppl. 

 t. 2732. C.aquatica, 7. E. Bot. t. 722, (the small figure.) 



Ditches near Lough Neagh ; Mr. Templeton and Mr. D. Moore. 

 Fl. June Oct. 0. Leaves always sessile, (W. Wilson.) C. Pe- 

 dunculata described by Doctor Hooker and Mr. Arnold, in the works 

 above-mentioned, I have not found in Ireland. 



ORD. 68. CERATOPHYLLE^. D C. Hornwort Family. 



Flowers monoecious. Calyx free, many-parted ; the lobes 

 equal. Petals none. Masc. Stamens 12 20, without fila- 

 ments : anthers ovato-oblong, 2-celled, with two or three points 

 at the apex, collected into the centre of the calyx. Fem. 

 Ovary free, ovate, 1-celled : style filiform, incurved, oblique : 

 stigma simple. Nut 1-celled, 1-seeded, apiculated with the 

 persistent style, indehiscent. Seed pendulous. Albumen none. 

 Embryo straight : radicle superior : cotyledons 4, whorled, 

 alternately smaller, with a much divided plumule. Aquatic, 

 submerged herbs, distinct as an Order but of very doubtful affi- 

 nity ; with whorled rather rigid leaves, cut into slender segments 

 and somewhat serrated. 



1. CERATOPHYLLUM. Linn. Hornwort. 



Barren fl. Calyx inferior, multipartite. Corolla none. Sta- 

 mens 16 20. Fertile fl. Calyx multipartite. Corolla 

 none. Germen one. Style filiform, curved. Stigma simple. 



