44 2 



CERATOPHVLI.E.E 



leaves, slaiiieiis a — 20; ovary 2 chambered; sivles 2, long; ovules 

 2 ; fruit capsular. (Name in honour of the heathen god Mercury.) 



1. M. percnnis (Dog's Mercury). Rhizome slender, creeping; 

 stem solitary, erect, about a foot high, uhbranched ; leaves oblong- 

 lanceolate, rough, hau-y ; flowers small, green, on peduncles 

 springing from the axils of the upper leaves, the staminate ones 

 \n racemes, the carpellate in spikes, : Woods ; abundant. — Fl. 

 April, May. Perennial. 



2. M. diuiua (Annual Mercury). — A much branched, nearly 

 glabrous species, with sessile leaves of a light green, and some- 

 times with moncecious flo'icers. Cultivated land; not common. — 

 Fl. July — October. Annual. 



Okd. LXXIII. (Jekatophvllr.e. — The FTornwort F^iiiLY 



An Order containing only the one genus Ceratopliyllum, tl.e 



Hornworts, a group of one or 

 two species of submerged 

 aquatic plants that are unim- 

 pjrtant except from their 

 structure, which is so distinct 

 from, that of any other known 

 Dicotyledon as to render their 

 affinities doubtful. They have 

 long; slender, brittle, brancheil 

 items ; whorled, sessile, e.\- 

 stipulate leaves, which are 

 2 — 4 forked into antlcr-like 

 narrow lobes ; and minute, 

 axillar)', moncecious flowers, 

 enclosed in an S — 12-leaved 

 involucre with bristle-like, per- 

 sistent lobes. Tlie stamens 

 are 12 -20, without filaments, 

 but with 2 points to each 

 anthf;r ; the ove.rv is i-cham- 

 bered, i-ovuled; style 1, 

 curvfed ; jruit an indehiscent 

 achene, sometimes with 2 

 spines at its base. ( Name from 

 the Greek hcras, an antler, 

 phutlon, a leaf, from the form 

 of tlie leaves.) 



{I niir}J!pn / /ormi'ijri). 



Ceratophvllum (Flornworl). 



