66 5 
Macroglossum Alidae, Copeland. 
A section of the leaf passing through the sorus (Text-fig. 8) shows the 
conspicuous bundle belonging to the vein above which the sorus lies ; and 
below the vein is a large mucilage duct. Occupying the centre of the 
ridge between the sori is a group of sclerenchyma cells, which form 
a pseudo-vein, which is very evident in horizontal sections. These 
in] 
Text-fig. 8. Cross-section of a sporophyll passing through a sorus. x about 35. tn., mucilage 
duct ; in., indusial hairs. 
sclerenchyma cells stain strongly with safranin. Very large intercellular 
spaces are developed in the mesophyll, whose cells are very much elongated. 
A very conspicuous palisade tissue is present below the ventral surface of 
the leaf, and this palisade tissue is separated from the epidermis by a single 
layer of colourless hypodermal cells. Stomata were observed only on the 
dorsal epidermis. 
The Systematic Position of Macroglossum. 
In view of the fact that Raciborski considered the specimen of Macro- 
glossum growing at Buitenzorg to be a species of A ngiopteris, it may be 
well to summarize the points of difference between Macroglossum and 
Angiopteris . 
The gametophytes are very similar, but the antheridia of Macro- 
glossum develop a much greater number of spermatozoids than are found 
in Angiopteris . The spermatozoids are somewhat smaller and relatively 
shorter, resembling in the latter respect those of Danaea. 
The embryo differs from that of Angiopteris in the very important fact 
that it develops a large suspensor, thus again suggesting a remote relation- 
ship with Danaea , The later development of the embryo, while perhaps 
most nearly approximating Angiopteris , nevertheless, is in some respects 
