460 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



European or southern sjiecies. India and Java have their re- 

 presentatives, but they are not in general cosmopolites. As 

 the name expresses, the distinguishing character is the absence 

 or slight development of the perianth. In Alicularia, how- 

 ever, the toothed edge is free. A. scalaris is a common species 

 upon loamy soil, in woods and waste places. The calyptra is 

 shorter, and surrounded at the base by abortive archegonia. 

 Sarcoscyphus, also, has the edge of the perianth free, and the 

 stem, though at first creeping, becomes erect at the tips. 8. 

 Ehrarti, the old Jungermannia emarginata, is a common 

 Alpine British species. Sir W. J. Hooker, in company with 

 Mr. Borrer, found examples with two or even three sporangia 

 in the same involucre, a very uncommon circumstance. Aero- 

 bolbus Wilsonii, which was found near KiUarney, resembles 

 Geocalyx in its descending radiculate involucre, but is distin- 

 guished from similar productions by its succubous leaves. 

 Gymnomitrium has no perianth, unless it be the inner mem- 

 branous leaf of the involucre, which conceals the calyptra, 

 Haplomitrium, on the contrary, has the calyptra longer than 

 the involucre, without any perianth. The only species, H. 

 Hooheri, is classical, from the excellent memoir of Gottsche, 

 illustrative of it, in Act. Ac. Gees. Nat. Gur., vol. xx. The 

 involucre itself is scarcely developed, or differentiated from the 

 other leaves. Some of the upper leaves have retort-shaped 

 cells attached to the margin, which may possibly be repro- 

 ductive. 



606. The limits of the species of Jungermanniw in gene- 

 ral, are at present very imperfectly understood. It is quite 

 certain that many FruUanice must be reduced, and the same 

 may be said of other species belonging to prolific genera. It 

 is at least clear that many of the commonest species are sub- 

 ject to great variations as regards size, colour, length of the 

 peduncles, the form of the leaves, their closer or denser arrange- 

 ment on the branches, and even in the appendages on their 

 lower margin. Fruit is comparatively so rare, that we cannot 

 always appeal to it, its place being supplied by reproductive 

 gems. The serration of the leaves, again, is extremely vari- 

 able, sometimes occurring only on the upper limb, sometimes 



