Boodle . — A natomy of the Gleicheniaceae , 7 1 5 
elements (sc.), which have not the brown walls characteristic 
of the cortex. The pericycle on the outer side of the 
bundle is 3-4 cells thick, and bounds the drawing. In a 
section of another petiole of G. dicarpa each of the two 
lateral protoxylems was split into two slightly separated 
groups. The difference in structure at the base of the petiole 
in this species will be described in connexion with the node. 
The other species of Eugleichenia have petioles of the 
same type as G. dicarpa ; that is, the endodermis is not 
invaginated, the xylem forms an arch, and three similarly 
placed protoxylem-groups are present. 
There are considerable differences in the size and proportion 
of parts in these other species, but the type of structure is 
practically the same. In G. circinata the structure is very 
similar to that of G. dicarpa. In G. Boryi, which has a much 
smaller petiole, no sclerotic cells are differentiated in the 
central tissue, and fibrous constituents of the phloem appear 
to be quite absent. In G. moniliformis also the bundle is 
small, the xylem-arch has more the form of a narrow U, 
in which the hooks are hardly represented, the phloem is 
only continued a short way up in the interior, and only about 
two sclerotic elements were found in the central parenchyma. 
In G. polypodioides the structure at first sight looks very 
different, as it shows an almost solid-looking mass of xylem, 
shaped something like an equilateral triangle with rounded 
angles. It may, however, be referred to the same type as the 
other species. The differences of detail are as follows: — in 
G. polypodioides the central mass of tissue (which in G. dicarpa 
includes the sclerotic tissue, sc.) is only represented by 
a narrow line of parenchyma, one to two cells thick 1 ; the 
hooks of the xylem have only narrow bays, containing 
parenchyma and fibrous phloem-elements, which are con- 
tinuous with the phloem bending in through the small space 
1 In G. circinata a transverse section of a young petiole, with protophloem and 
protoxylems differentiated, showed an arrangement of the cells in the central mass 
of parenchyma, which gave evidence of comparatively late cell-division, apparently 
deriving the group from a single median row of cells. 
