433 



Fig. 501. 



HEPATIC^. 



The Scale-mosses are minute creeping plants with small, green, cel- 

 lular (scale-like) leaves, imbricately arranged along the axis in two 

 rows, often with a row of imperfect leaves (ampldyastria, fig. 501, d) 

 on the underside ; or with the stem thalloid, i. e. forming a lobed leaf- 

 like mass. The sporangia have oval capsules breaking through the 

 summit of the calyptra, raised on a thread-like seta, and splitting ver- 

 tically when ripe into 4 valves, which separate more or less widely into 

 the form of a cross (tig. 501, B) ; scattering spores mixed with elaters, 

 destitute of a columella. 



The Jungermanniese (or foliaceous Hepaticae) have slender ramified 

 creeping stems like those of branched 

 Mosses, being more delicate, with 

 leaves imbricated in a distichous 

 manner, so as to give a flattened 

 character to the branches (fig. 501, 

 B, d). The antherldia and archeyo- 

 w'aare produced on these stems ; and 

 from the latter are developed the spo- 

 royonia, which are surrounded at 

 the base by modified parichcetial and 

 periyonial leaves and by a vayinule 

 (fig. 501, B, ), which differ* from 

 tli at of the Mosses in being the en- 

 tire sac of the archegonium, no 

 hooded calyptra being carried up in 

 the Jungermanniere. The vayinule 

 is sometimes called calyptra, and 

 sometimes epigone \ the circle of 

 leaves, often confluent, surrounding 

 it form the periffone, perianth, or 

 involucel ; and these are surrounded 

 by the pericJustial leaves, pericha- 

 tium, or involucre. The capsules are 

 generally elevated on thread-like 

 stalks (seta), and when mature split 

 nearly or quite to the base into four teeth (fig. 501, 6), which spread out 

 more'or less, and set free the spores and elaters (c). There is no columella. 

 The genera of this Order, formed out of the old genus Junyermannia, 

 present a considerable variety of conditions, both as regards their vege- 

 tative structure, which is either frondose or foliaceous, and the minute 

 details of the organization of the calyptra (epigone), with the involucel 

 (perianth or periyone) and the involucre (perichcetium) which surround 

 it. We have here a higher condition of the vegetative organs, nearer 

 that of Mosses. The Jungermanniese are found in shady woods and moist 

 situations throughout all regions of the globe, and are most abundant in 

 damp tropical woods. They have no important qualities. 



The ANTHOCEROTE^: are distinguished from the frondose forms of Jun- 

 germanniese by the absence of an involucel (periyone). The anther idia 



Organization of Jungermanniaae : B. Hadula. 

 complnnata with an unopened and a burst 

 capsule : a, the vaginule ; b, the burst capsule, 

 magnified; c, spores and elaters ; d, fragment 

 of the leafy stem of Jungermannia, umbrosa, 

 showing the distichous arrangement of the 

 leaves, and the amphignstria (e). 



