388 
lxxix. ceratophyllacejE. [ Cera tophyllu m . 
constantly erect, var. /3. to have them reflexed when in fruit ; but in 
the former we find them to he usually as much reflexed as in the 
other. Mr. Bentham considers that there is but one species of the 
genus (O. aquatica ), which has been “variously divided into from 2 
to about 20 supposed species ; but the distinctive characters which 
have been given all fail when applied to a large number of specimens 
collected in different parts of the world.” 
2. C. pedunculuta DC. ( pedunculated W.) ; fructiferous pe- 
duncles without bracteas at the’base, fruit, regularly tetragonal, 
each lobe bluntly keeled at the back. C. autumnalis Hook, in 
E. B. S. t. 2606 (ex cl. the syn.). 
Ditches in Jersey, Sussex, Shropshire, Wales, &c. ©, 6 — 9. — 
Fruit sometimes almost sessile. 
3. C. autumnalis L, ( autumnal W.) ; fructiferous peduncles 
very short without bracteas at the base, fruit irregularly tetra- 
gonal, each lobe broadly and acutely winged at the back. 
E. B. S. t. 2732. C. aquatica y. Huds.: E. B. t. 722 (the small 
figure). 
Ditches and lakes. Anglesea. Loch of Cluny, Perthshire ; Lochs 
near Forfar ; Loch of Drum, Kincardineshire ; Scotland. Cong, 
County Mayo. 0. 6 — 10. 
Ord. LXXIX. CERAT0PHYLLACE2E Gray. 
Flowers imperfect, monoecious. Perianth (involucre?) single, 
free, 10— 12-clefr. — Barren jl. Anthers 12—20, sessile, 2- 
celled, 2 — 3-cuspidate. — Fertile Jl. Ovary superior, solitary, 
bicuspidate above the base, 1-celled, with one pendulous ovule. 
Style oblique, filiform, at length hardened, persistent. Stigma 
simple. Fruit an achene, 1 -seeded. Albumen 0. Embryo 
straight ; cotyledons 2, oval, fleshy ; plumule many-leaved, highly 
developed, its lower pair of leaves being separated from the 
others by an nite’mode and close to the cotyledons, thus resem- 
bling two narrow inner ones decussating with the outer ; radicle 
inferior. — An aquatic Order comprising one genus of doubtful 
affinity. Leaves ivhorled, rigid , dichotomous , with narrow ser- 
rate segments. 
1. Ceratophvllpm Linn. Hornwort. 
Character same as of the Order. — Name: ki pac, ssparoc, a 
horn, and QvWov, a leaf; from the forked leaves. 
1. C. demersvm L. (common II .) ; achene armed with two 
long rigid spines near the base and terminated by the longish 
subulate style. — n. spines of the fruit terete. E. B. t. 947. C. 
oxyacanthuin Cham . — d. * spines of the fruit laterally com- 
pressed and winged at the base. C. platycanthum Cham. 
