Boodle. — A natomy of the Schizaeaceae. 4 1 1 
not seem to have arrived, but ‘ dialystelic ’ and ‘ solenostelic ’ 
are convenient words for describing structures like those of 
Anemia Phyllitidis and A. mexicana , whether they are really 
based on the disposition of the whole stelar tissue, or of the 
part of the stele which shows typical stelar characters. The 
separate parts of the dialystelic type have here been usually 
spoken of as e steles 1 ; but ‘ meristeles ’ or 4 dialysteles ’ would 
be perhaps a preferable term, if one regards them as being 
only circumscribed parts of a stele. 
Comparison of Structure. 
Some points of agreement and difference between the 
structure of the genera of Schizaeaceae should now be re- 
ferred to. 
A single leaf-trace passes off to supply each leaf, and is 
continued as the petiolar bundle which remains undivided. 
In the bundle of the petiole (of three of the genera) a median 
protoxylem-group is present on the upper side of the xylem. 
Two other protoxylem-groups, which are also on the upper 
side of the xylem, may also be present (e. g. Anemia). In 
Lygodium , on the other hand, two approximated groups of 
protoxylem separated by the median plane are present on 
the lower side of the xylem. These, however, tend to fuse 
into one median group towards the base of the petiole, and 
in L. palmatum one median group is found in the petiole. 
In all the species of Lygodium , besides the protoxylems 
mentioned, two lateral external groups are also present. The 
two nearly median protoxylem-groups have probably been 
produced by the splitting of a median single group, as found 
near the base of the petiole, for that is probably a less modified 
region. Therefore L. palmatum , with its undivided median 
protoxylem, shows a less modified structure than the other 
species, and it is noteworthy that in this species the median 
group is not peripheral but embedded in the xylem. A 
possible explanation of the great difference in type between 
the bundle of Lygodium (Fig. 4) and that of Anemia (Fig. 17), 
is that in Lygodium there has been a large addition of xylem 
