BRITISH HEPATIC /E. 43 



The leaves (f. 2) are inserted obliquely, contracted at the base, 

 nearly plane, horizontal at the inferior portion of the shoots, but 

 more concave (f. 4), ascending, and connivent near the apex. 



' AmpUgastria wanting on the barren stems, although I have 

 observed minute ones once or twice at the apex of innovations 

 (f. 33, 8), either lanceolate, or ovate and bi-dentate in form. 



Texture of the leaves thin but not translucent, little altered 

 when dry ; colour yellowish-green, the basal leaves darker. 



Leaf-cells (f. 33, 5) roundish-hexagonal, with well-defined, equal 

 walls, the marginal cells having no special form. Diameter in the 

 upper part of the leaf about yp"o "j iiear the base the cells are oval, 4^" 

 by -g-8o"- Trigones imperceptible. Within the cells we find numerous 

 minute chlorophyll granules. On the exterior of the involucral 

 leaves of one specimen I observed the cells remarkably prominent, 

 resembling those of Lejeunia ecMnata, and some of them prolonged 

 into rootlets. In Jung, capitata the cells are larger and more trans- 

 lucent, and the walls thinner. 



Fructification terminal, but from the growth of innovations 

 sometimes appearing lateral. 



Involucral leaves (f. 32, 3) originally free, two in number, much 

 larger than the rest, broadly ovate or cordate, 2- to 3-lobed, the 

 lobes repand-dentate, so as to have a crisped appearance, convolute- 

 concave, base saccate-ample'xicaul. Between the two a semi-ovate, 

 acuminate ampMgastrium is interposed (f. 33, 3), irregularly dentate 

 at the margin. The involucral leaves are originally free, surround- 

 ing the convex apex of the stem, on which 15-20 pistillidia are 

 crowded. But after impregnation, the rapid cell-growth of the youn g 

 germ extends to the ' torus pistillorum,' and the bases of the adja- 

 cent leaves, so that the whole are blended together, forming an 

 involucre (f. 33, 4) about a line in length, the lower half of which 

 is ob-conic and entire, projecting below the level of the stem, and 

 forming a kind of bulb, from which numerous rootlets proceed. 

 Tlie mouth of the involucre is surmounted by the connivent 

 involucral leaves, which retain their old form ; M'hilst its base is 

 hidden by the suId -involucral leaves (which approach the terminal 

 ones in size), and are toothed in a similar manner. 



On longitudinal section (f. 33, 6) the structure \vill be better 

 understood. The capsule 'is found occupying a cavity, composed 

 in part of the metamorphosed apex of the stem and bases of the 

 involucral leaves, and in part of the calyptra, which, with the 

 exception of its dome-like apex, is concrete with the outer walls, 

 bearing around it the remains of the abortive pistillidia, which, 

 intermingled with minute bracts, surround the mouth of the 

 involucre like a fringe. 



Colesule wanting. 



Calyptra campanulate, of thin hyaline texture, adnate (except 

 at the apex) with the fleshy involucre (f. 33, 6, 7). 



