20 INTRODUCTION. 



either inflated or partially inrolled or cucullate — 

 sometimes even bell-shaped or cylindrical — is 

 almost unknown in Jungermanniece. Several genera 

 possess a character entirely unknown among Jitbu- 

 Icce, viz., a perianth that is wide-mouthed through- 

 out its existence, and therefore needs not to be rup- 

 tured for the emission of the capsule. The calyptra, 

 as compared with the perianth, is of various lengths, 

 being in some species scarcely at all shorter, but in 

 others four times as short. The character of an in- 

 ferior or half inferior calyptra, occurring in several 

 genera of Jungermanniece, is quite unknown in Ju- 

 Inilac. Elaters numerous — sometimes to be counted 

 by thousands, produced on the whole inner surface 

 of the capsule, usually slender and tortuous, nar- 

 rower at each end (never truncate), and each in- 

 cludes two spiral fibres — rarely three or more — very 

 rarely only one. When the capsule bursts they 

 mostly fall out all together along with the spores. 

 Spores very numerous and usually very minute, in 

 only a few genera equalling these of the Jubulea ; 

 nearly always globose. 



The Jungermanniece are further sub-divided into 

 eight sub-tribes, of which seven have the elaters 

 normally bispiral. That is to say — the Radulece, 

 I \ vr//ra\ PtilidiecB, Trigonanthece, Scapanioidece^ 

 Epigonianthece and Fossombroniece. The eighth,Mete- 

 .v<<\ has the elaters monospiral, and at the same 

 time the species are frondose. The relations of 

 these several tribes to each other will be found 

 under each, as hereafter follows : — 



-b 





