CERATOPHYLLACEiE. 123 



margins of lobes rounded without any keel or wing. Althougli 

 C. truncata is mainly a southern form, yet as it occurs as fur north as 

 Belgium it is possible that, in some of the British stations recorded for 

 C. autumnalis, C. truncata may yet be found. 



Autumnal Water Starwort. 



German, Herhst Wasseystern. 



ORDER LXX.— CERATOPHYLLACE^. 



Small diffusely branched rigid brittle herbs, growing in water and 

 entirely submerged. Leaves sessile, verticillate, wedgeshaped, dicho- 

 tomously cleft into numerous slender acute segments. Flowers monoe- 

 cious, sessile, axillary, solitary, very minute, bracteate, with an involucre 

 cut into 10 or 12 segments. Perianth none. Stamens in the male 

 flowers 12 to 20; anthers sessile, 2-celled. Female flowers with a 

 1-celled ovary; ovules solitary, pendulous, orthotropous ; style single; 

 stigma filiform, oblique. Fruit a 1 -seeded indehiscent nut, tipped 

 with the hardened style. Seed solitary ; albumen none ; embryo with 

 2 cleft cotyledons ; radicle inferior. 



G^^iV^ra J— CERATOPHYLLUM. Li?m. 

 The only known genus of the order. 



The derivation of the name of this genus of plants is from Kepa^ (Leras), a horn, 

 and (l>v\Xoy (phullon), a leaf, the leaves being supposed to resemble little horns. 



SPECIES I.— C ERATOPHYLLUM A QU AT I CUM. Wats. 



In Lond. Cat. ed. vi. 

 Plates MCCLXXVI. MCCLXXVIL 

 C. demersum, Benth. Handbk, Brit. Bot. ed. ii. p. 12 (non Linn.). 

 The only known species. 



Sub-Species I.— Ceratophylluin demersum. Limu 



Plate MCCLXXVI. 



Billut, Fl. Gall, et Germ. Exsicc. No. 3084. 



Fruit smooth, with a spine on each side near the base, and tipped 

 with a long curved subulate style. 



In ponds and ditches. Rather common in the south of England ; 



B 2 



