Asexual Reproduction in Hepaticae. 133 
superficial cells of the stem. Leitgeb 1 worked out the development 
of tl ese branches in Cephalozia bicuspidata and in Lophocolea 
bidentata. In both of these commonly-occurring forms, the writer 
has found that the older parts of the plant frequently bear 
adventive shoots, each of which arises from a single leaf-cell or 
superficial stem-cell. In these old and more or less decayed parts, 
the cells are often filled with branched and coiled fungal hyphae and 
have become brown, but here and there we find cells which have 
retained their living protoplasm and are free from fungal attack, 
and it is from such cells that the adventive shoots are developed. 
As a general rule, the shoot springs immediately from the surface 
of the leaf or stem, but sometimes the parent cell grows out to form 
a long tube, the distal end of which swells up and undergoes 
repeated divisions to form the growing-point of the new shoot. As 
a general rule, the adventive shoot becomes detached from the 
parent plant at an early stage, but sometimes it remains attached 
until it has formed a considerable number of leaves and a few 
rhizoids. Such a case of vivipary was observed in Lophocolea 
bidentata by Massalongo, 2 who figures a leaf bearing three young 
plants; two of them replace the pointed lobes of a normal leaf and 
are furnished with rhizoids. As will be pointed out later in dealing 
with gametophytic regeneration in Hepaticae, adventive growths of 
this kind are often abundantly produced on leaves which have been 
isolated and kept under cultivation, but it is interesting to find that 
the process of regeneration may also occur in nature, the viviparous 
shoot reaching a fairly advanced stage of development before 
becoming severed from the parent plant. 
1 Leitgeb, H., Uiitersuchungen iiber die Lebermoose, Heft 2, 
1885, p. 38. 
2 Massalongo. C., Sopra uu interessante caso di viviparita 
nelle Epaticlie. Bullettino della Soc. bot. ital., 1901 ; 
reprint of 4 pp. 
(To be continued). 
