BRITISH HEPATICiE. 3 



when quite young, and consisting only of few cells, bears at its 

 apex (or when multi-angular at each of its angles) a clavate, bent, 

 retort-shaped cell, which in a fully- deyeloped leaf, consisting of a 

 great number of cells, is still found in the corresponding position." 

 This fact proves that the leaf of Jungermannia is not the result 

 of the division of a single apical cell, but that there is a tendency 

 in the longitudinal halves of the young leaf-rudiments to develop 

 independently, and often unequally; 



Posterior row of leaflets (amphigastria) somewhat smaller, but 

 otherwise resembling the rest. 



Texture of the leaves soft, laxly and somewhat coarsely reti- 

 culate, shrinking considerably when dry, and recovering their form 

 very slowly and- imperfectly. 



Cells uniform, destitute of ' trigones,' those near the apex irre- 

 gularly quadrangular, from y^ to -5^ of an inch long, and ttVo" 

 to xtt^' broad. The lower cells are longer, and hexagonal. They 

 contain numerous chlorophyll-corpuscles of a bright-green colour. 



Involucral leaves resembling those of the stem, but larger, at 

 first erect and connivent, so as to enclose the pistUlidia, at length 

 patent or reflexed. 



Colesule wanting. Calyptra, when mature, linear oblong, fleshy, 

 equalling the stem in length. Pedicel an inch long, succulent, white. 



Capsule cylindric-oblong, pale-brown, opening by two or four 

 valves, which are frequently held together by the Maters, which 

 are bi-spiral, and attached to the apex of the valves, and persist 

 until the decay of the capsule, spreading out in a flabellate manner. 



Spores roundish or tetragonous, cristate-crenate, reticulate, red- 

 dish-brown. 



Antheridia globose, shortly stipitate, golden-yellow or olive, 

 seated to the number of 5 or 6 in the axils of the superior leaves 

 of the male plant. 



The perigonial leaves are recurved, and scarcely ventricose at 

 the base, so that the antheridia are exposed, and from their orange 

 colour form a very beautiful object under the lens, nestling among 

 the green leaves, like the fruit of the orange- or lime-tree. 



Pl. I. Fig. 1. — 1. Scalitjs Hookeri, fronds Tuxtwral size. 2." Fertile shoot 

 X 16 diam. 3. Male shoot x 16 diam. 4. Mater and spores x 250. 5. 'Antheridiwm. 



Section II.— Ccelocaules. 



G. L. & N. ah E. Syn. Hepat. p. 13 (1844) ex parte. 



Thalamomitriese, Lindherg <m Zoopsis, Jour. Lin. Sac. v. xiii. p. 193, &c, (1872). 



Calyptra combining with the hollow apex of the stem, and 

 involucral bracts, to form a " rachideal pouch," within which the 

 sporangium lies, fructification terminal, sub-terminal, or arising 

 from the axil of an amphigastrium, at length lateral. 



