F. Cavers. 
156 
of the main stem or of its branches often becomes entirely given 
over to the production of a rounded mass of gemmae; these 
gemmiferous shoots often grow erect and assume apparently radial 
symmetry, the amphigastria becoming here similar in form to the 
lateral leaves and like them producing strings or clusters of 
gemmae, whilst the shoot is terminated by a globular mass 
consisting of branched rows of gemmae (Fig. 6 ). 
Fig. 6. Ccphalozia bicuspidcita. Longitudinal section through the apex 
of an erect gemmiferous shoot, showing two of the reduced leaves and 
numerous gemmae, some arranged in branching chains, x 150. 
The gemmae may be either (1) uni- or bi-cellular bodies, formed 
singly or in chains and branched clusters on the margins of the 
leaves or the summit of the stem ; or (2) discoid multicellular 
bodies arising on the margins or the surfaces of the leaves. 
The uni- or bi-cellular gemmae are usually spherical or ovoid 
in form (Fig. 6 ), but sometimes they are tetrahedral 
Lophozia ventricosa ) or polygonal [^.g., Diplophyllum albicans 
(Fig. 7 )]. In most cases they are green or yellowish in colour, but 
frequently they are red, brown, or purple ( e.g ., Scapania nemorosa). 
Discoid gemmae occur in the families Stephaninoideae 
(Radula ), Bellincinioideae ( Porella ), and Jubuloideae ( Frullania , 
Lejeunea) ; whilst uni- or bi-cellular gemmae are found in all the 
remaining families, except the Pleurozioideae ( Pleuvozia ). Gemmi¬ 
ferous species occur in the great majority of the Acrogynous 
genera, and it would appear that the production of gemmae plays 
