F. Cavers . 
216 
upper surface of the stem and are protected by the young leaves 
at the stem-apex; but this difference is clearly correlated with the 
fact that Pellia is thalloid while Noteroclada is foliose. Stephani 
(66) says that Noteroclada is so near Pellia that it should perhaps 
be included in that genus, and that it is practically a Pellia calycina 
with stem and leaves instead of simple thalloid plant-body. 
In Blasia there is a broad stem bearing on either side a row of 
large leaves lying in the same plane as the broad midrib or stem, 
and not so sharply separated from it as in Noteroclada. In addition 
to the leaves, Blasia developes an extraordinary diversity of 
appendages—iVosfoc-auricles and amphigastria on the lower surface, 
curious flask-like gemma-receptacles and star-like gemmae on the 
upper surface. The amphigastria on the lower side and the star- 
like gemmae (5) on the upper are alike in structure, being cell- 
plates attached by a short stalk at the centre ; the former stand 
singly at the junction of leaf and stem, the latter are scattered 
over the upper side of the thallus and on being detached give rise 
to new plants. The long-necked gemma-flasks have been described 
and figured already in this journal (7). The iVos/oc-appendages 
(17, 41, 53, 70), of which there are usually two to each leaf, when 
ready for infection by Nostoc, are rounded pockets, each formed 
from a cell which projects from the thallus and divides transversely, 
cutting off a terminal club-shaped slime-secreting cell, around which 
the auricle grows like a hood by division of the underlying cell. 
After the entrance of the Nostoc, the opening closes up and the 
whole auricle increases in size ; as the Nostoc chains grow, the 
slime-secreting cell projects into the cavity and branches to form 
a tree-like structure, the ramifications of which doubtless absorb 
nourishment from the algal cells. The flask-like gemma-receptacles 
are probably modified archegonial receptacles, since archegonia 
are sometimes found in these flasks. The antheridia and arche¬ 
gonia have the same arrangement and structure as in Pellia, but 
the capsule (1, 52) differs considerably from that of Pellia, being 
elongated and having its basal portion produced downwards as a 
collar around the top of the seta. There are no ring-like fibres in 
the capsule wall, which consists of an outer layer of large cells 
with rodlike thickenings on the radial walls, and two or three inner 
layers of flattened and thin-walled cells; at the base of the 
capsule there are a few fixed elaters, representing a rudimentary 
elaterophore. 
The Japanese genus Cavicularia closely resembles Blasia in 
