( 260 .) 
CERA/rOPHY'LLUM* * 
Linnean Class and Order. Moncecia f , Polyan'dria. 
Natural Order. Ceratopiiyllea;, Gray’s Nat. Arr. of Brit. 
Plants, v. ii. p. 554. — De Cand. Prod. v. iii. p. 73. — Lindl. Syn. p. 
225. ; Tntrod. to Nat. Syst. of Bot. p. 176. — Loud. Hort. Brit. p. 514. 
— Don’s Gen. Syst. of Gard. and Bot. v. ii. p. 705. — Mack. FI. 
Hibern. p.239 . — Naiades, Jiiss. Gen. PI. p. 18. — Sm. Gram, of 
Bot. p. 66 . — Quernf.ales; sect. Hippuri.v.e ; type, Cerato- 
phyi.laceae ; Burn. Outlines of Botany, pp. 523, 576, & 578. — 
I.vu.ydat.e, Linn. 
Gen. Char. Barren Flower (fig. 1). Calyx inferior, in many, 
deep, equal, oblong, permanent, upright segments. Corolla none. 
Stamens twice as many as the segments of the calyx, from 12 to 
20, without filaments. Anthers oblong, upright, rising above the 
calyx. Fertile Flower (f. 2.) Calyx as in the barren flower. Corolla 
none. German (see fig. 2.) superior, egg-shaped, compressed, 1- 
celled. Style scarcely any. Stigma (see fig. 2.) simple, thread- 
shaped, oblique. Nut (fig. 3.) somewhat egg-shaped, compressed, 
1 -ceiled, 1-seeded, indehiscent, crowned with the permanent, 
hardened stigma. Seed (see fig. 5.) solitary, the shape of the nut 
(see fig. 4.) ; with 4 cotyledons, alternately smaller ; and a many- 
cleft, central embryo (see fig. 7). 
The manv-cleft calyx; want of a corolla; the number of sta- 
mens in the barren flower , from 12 to 20 ; and the nearly sessile, 
thread-shaped, oblique stigma; and superior, 1-seeded nut of the 
fertile flower ; will distinguish this from other genera in the same 
class and order. 
Two species British. 
CERATOPHY'LLUM DEME'RSUM. Demersed Hornwort. 
Common Hornwort. 
Spec. Char. Fruit armed with 3 spines, which are unequal, 
one terminal, and two lateral. Segments of the calyx notched at 
the extremity. 
Perennial. — Flowers in August and September. 
Engl. Bot. t. 947 Linn. Sp. PI. p. 1409.-Huds. FI. Angl. (2nd ed.) p. 419, a. 
— Willd. Sp. PI. v. iv. pt. i. p. 405.— Sm. FI. Brit, v.iii. p. 1020. ; Engl. FI. v. iv. 
P- 141. — With. (7th ed.) v. ii. p. 572. — Lindl. Syn. p. 225. — Hook. Brit. FI. p. 
405.— Lightf. FI. Scot. v. ii. p. 580 — Sibth. FI. Oxon. p. 168.-Relh. FI. Cant. 
(3rd ed.) p. 392. — Purt. Midi. FI. v. iii. p. 70. — Hook. FI. Scot. pt. j. p. 272. and 
pf. u. p. 297.— Grev. FI. Edin. p. 201.— FI. Devon, pp. 154 & 195.— Winch’s 
FI. of Not thumb, and Durham, p 61.— Don’s Gen. Syst. of Gard. and Bot. v.ii. 
p. 705.— Walker’s FI. of Oxf. p. 279.— Bab. FI. Bath. p. 17.— Mack. Catal. of 
PI. of Irel. p. 82. ; FI. Hibern. p. 240. — Ceratophyllum cornutum, Rich. Mem. 
Mus.- Gray’s Nat. Arr. v. ii. p.554 .—Dichotophyllon, Dill. Giss. p. 149.— 
Hydroceratophyllon folio aspero, quatuor cornibus arrnato, Ray’s Syn. 
p. 135. 
Fig. 1. A Barren Flower. — Fig. 2. A Fertile Flower. — Fig. 3. Fruit. — Fig. 4. 
A vertical section of the Fruit or Nut. — Fig. 5. Seed. — Fig. 6. A transverse section 
of the Nut . — All more or less magnified. 
* From Iceras, Gr. a horn ; and phyllon, Gr. a leaf; in reference to the leaves 
being branched, like a stag’s horn. Don. 
t See folio 83, note f. 
