S. L. Ghose 
56 
on opposite sides. It may be suggested that this abnormality has been 
brought about by fusion of two opposite leaves by their “petioles” 
and “midribs”; but it does not seem likely, as there is no indication 
whatsoever in the internal tissues to show that any fusion has taken 
place, while the three-“ribbed” condition of the “petiole” can easily 
be brought about by a process of flattening, which is accompanied 
by the production of two opposite invaginations. Figs. 6-10, which 
are merely hypothetical, might very well represent what has actually 
happened in the specimen. Figs. 9 and 10 are fairly comparable 
with some diagrams given by Arber (1921, Figs. 56, 57) in connection 
with the formation of blades by this process of invagination amongst 
the Irids. Celakovsky’s diagrams of sections of the leaves of Crocus 
and Ferraria (1892, Figs. 32 and 40) are also interesting in this con¬ 
nection. They suggest the possibility of the formation of two blades 
by such a process of invagination. The bundles, however, seem to 
have similar orientation, most probably on account of the non¬ 
completion of the vascular ring in the “petiole,” and marked growth 
of tissue at the “open” region. The orientation of bundles may be 
different according to the plane of the invagination, the completion 
or otherwise of the ring of vascular bundles in the “petiole,” and the 
growth of various tissues at the time of expansion. In the case under 
discussion the last named factor may have been influenced by the 
“law of laminar inversion.” It may not be out of place to mention 
here that in the normal leaf of Allium ursinum the ring of bundles 
in the “petiole” is not complete, hence the leaf does not show 
“phyllode structure,” as has been noted by Arber (1920). Menz 
(1910, Text-figs. I-IX) gives some figures of Allium odorum L., in 
which this ring is nearly complete, so it seems not very improbable 
that in the case under discussion the ring may have been completed 
abnormally. Menz (1922, Text-fig. 3) also gives a diagram of a 
transverse section of a leaf of Allium nigrum L., a member of the 
same section of Allium —Molium—as Allium ursinum, which shows 
two series of bundles with opposed orientation, again showing the 
possibility of the completion of the ring of bundles in the abnormal 
“petiole” of the latter. It is possible to imagine that if the pair of 
invaginations had not existed in the abnormal case of Allium ursinum 
and the apex of the “petiole” had just expanded into one limb, the 
limb might have shown “phyllode structure,” as has been noted in 
many species of Allium by Arber (1920) and Menz (1922). 
In a recent paper, Gaisberg (1922) questions the validity of the 
Phyllode Theory and gives many arguments in support of the Midrib 
