34 BRITISH HEPATIC^. 



only disappears after prolonged (24 hours) treatment with strong 

 sulphuric acid." 



Infloresence paroicoiis. Fertile shoots thickened at the apex ; 

 colesule terminal, or rarely from the presence of innovations appear- 

 ing lateral. 



Involucral leaves (f. 35, 2, 3) two pairs, larger than the ordi- 

 nary ones ; upper pair equal, obovate, nearly opposite, connate with 

 each other, and with the walls of the colesule (which they closely 

 embrace) for more than half its length, patent or recurved at the 

 apex. Sub-involucral leaves vaginate at the base. On section the 

 base of one of these was found to correspond with the position of 

 the hollow torus pistillorum, whilst the axil of the succeeding leaf 

 enclosed two or three antheridia. 



Amphigastria : — one or two, lanceolate in form, may be per- 

 ceived attached to the involucral walls, and adnate with the 

 adjacent leaves ; they are absent from all other portions of the 

 plant. 



Colesule (f. 35, 3) obovate-oblong, about equal to the involucral 

 leaves, but from their recurvation the upper third is generally free 

 and exserted, slightly compressed, obtusely 5-6-plicate, apex conoid, 

 at length splitting into four acute lobes. 



Calyptra thickened at the base, and surrounded by numerous 

 abortive pistillidia, hyaline, reticulate, obovate. 



Capsule round, or roundish-obovate, dark brown, opening by 

 four ovate valves. 



Pedicel 6'" to 8'" long, white, hyaline-cellulose. 



Spores yellowish-brown, granulose, g^" in diameter. 



Maters enclosing a double spiral fibre, yyo" long, by ttfo" 

 broad. 



Antheridia axillary, inserted within the ventricose bases of the 

 sub-involucral and succeeding leaves, ovate to obovate, olive-green, 

 seated on a delicate stipe of four to six cells. 



Obs. — Nardia obovata is found in. similar situations to N. hyalina, and has pro- 

 bably not unfrequently been mistaken for that species. The diagnosis between the two 

 is sometimes far from easy, but in N. obovata the shoots are more erect and slender, 

 the leaves more ovate, distant, sub-squarrose, and saccate at the base, with entii-e 

 margins, and the involucral leaves adnate for more than half their length with the 

 colesule. 



From Jung, nana, sphcBrocorpa, &o., it may be distinguished by the white rootlets, 

 and free colesules of those species. 



From N. scalaris by the absence of amphigastria, except those that enter into the 

 composition of the involucre, and the colour of the rootlets. 



Dr. Gottsche (Hep. Eur. Ex. n. 266) has shown that IST. ab Es. understood this 

 species imperfectly, since in Leberm. Eur. ii. p. 471, several forms with purple rootlets 

 are referred to Jung, tersa, and this error is repeated in Syn. Hep., p. 94, n. 41. 

 The vars. a densa ( 7. Flotow), ft explanata, y rivularis, and S attenuata, Dr. Gottsche 

 states to be truly forms of iV^, obovata. 



