46 BRITISH HEPATICJ3. 



Shoots (f. 28, 1) one or two inches in length by a line broad, of 

 nearly equal diameter throughout, and from the regular imbrication 

 of the leaves, having a very neat appearance. Stems filiform, suh- 

 ligneous, slightly flexuose, but rigid and brittle when ".dry. Inno- 

 vations distant, ventral from the axils of amphigastria, patent, only 

 differing from the main shoots in size. Rootlets sparse, white, 

 most numerous at the bases of the amphigastria. 



Leaves (f. 28, 3) about half a line in length, distichous, closely 

 and regularly imbricated, alternate, or in some specimens nearly 

 opposite (f. 28, 2), horizontal, plane, or slightly convex on the 

 upper side, ovate to elliptic-ovate, obtuse, from a broad sub-decur- 

 rent base ; margins entire. 



Texture firm, dense', opaque. Colour green, ochraceous, or 

 olive-brown. Cells uniform, hexagonal, the walls not thickened ; 

 in the upper part of the leaf about ttto" i^ diameter ; near the 

 base glo" X too"- Trigones absent. The cells contain numerous 

 green granules, and a distinct nucleus. 



Amphigastria (f. 28, 4, 5) equal to half the diameter of the 

 leaves, broadly ovate-triangular, pointed, irregularly 2-3 dentate, 

 those near the base of the shoots being most divided; margin 

 reflexed, connate with the ventral border' of the left-hand leaf, 

 rarely with opposite leaves. 



The cell structtire resembles that of the leaves. 



Inflorescence dioicous. 



Fertile shoots (f. 28, 3) producing at intervals from the axils of 

 the amphigastria, minute, ovate, bud-like receptacles, clothed ex- 

 ternally with irregularly-dentate bracts (f. 28, 7), thick and succu- 

 lent at the base, and at first nearly sessile. On section from 6 to 

 12 fusiform pistillidia are found lurking within. 



After impregnation rapid cell-multiplication commences in the 

 tissues surrounding the young germ (calyptra) and the inferior 

 portion of the receptacle, during which the fleshy base elongates 

 and descends into the earth, forming, at length, " a hollow oblong 

 pouch or sac nearly a line long," and attached to the stem by a 

 short lateral pedicel proceeding from its upper border. When 

 mature the perigynium (f. 28, 6) is cylindrical in form, smooth or 

 irregularly striate, and of a brownish colour without, a little ex- 

 panded at the mouth, and surmounted by the modified involucral 

 bracts. After the egress of the capsule the sac becomes more fusi- 

 form, and the mouth contracts. 



Calyptra immersed, adnate with the walls of the sac for two- 

 thirds of its length. In young perigynia the hollow part above 

 the calyptra is contracted by the growth of clavate processes 

 from the walls, so that only a narrow channel remains ; and 

 the fruit-rudiment, from the rapid growth at the base of the 

 perigynium, lies in a hollow cavity, invested by a stratum of 

 mucus. 



