50 S. L. Ghose 
—one of the features distinguishing this specimen from a normal leaf 
of Allium ursinum. 
I cut transverse sections of the abnormal leaf at different levels 
to see the behaviour of the vascular bundles. Fig. 2 shows the trans¬ 
verse section at the place where the petiole was broken off. There 
are three series of bundles. The uppermost consists of two or three 
weak bundles with phloem towards the periphery; a few phloem 
elements sometimes occur on the lower side and on the flanks. The 
middle series consists of a large number of bundles, orientated like 
those of the uppermost series. The lowermost series is made up of 
io or 12 bundles, which, however, have an orientation opposite to 
that of the first two series. Higher up the bundles of the uppermost 
series unite with some bundles of the middle series, so that near the 
“laminar” portion the petiole has only two series of inversely 
orientated bundles. 
Fig. 3 shows the transverse section of the region where both 
blades are well developed. Here each blade has one series of bundles, 
but the orientation is opposite. There are two interesting points to 
be noticed in this section. Firstly, the stomata are found on the 
lower surface in the upper blade, but on the upper surface in the 
lower blade. Secondly, in the upper blade, the xylem of the bundles 
is found next the lower side, and not next the upper side as is usually 
the case in leaves. In order to explain these peculiarities, the structure 
of a normal leaf was studied. The anatomy of the genus has been well 
described by Irmisch (1850, pp. 1-25), Menz (1910 and 1922) and 
Arber (1918 and 1920). In Allium ursinum , in the underground 
portion the leaf begins at the base as a closed sheath round the apex 
of the condensed stem, and the bundles are arranged in a ring with 
their phloem towards the periphery. Higher up the leaf becomes 
thicker on one (dorsal) side and thinner on the opposite side. In the 
thicker side another series of bundles is developed towards the 
periphery by the splitting up of some of the bundles of the main 
series (Arber, 1920, Fig. 28 c). The orientation, however, is similar 
in both series. As we go higher up the ventral side gets gradually 
thinner till finally it disappears. The thicker side becomes rounded 
off and forms the “petiole” of the leaf (Arber, 1920, Fig. 28 d). In 
the “petiole” the bundles of the second series unite with some of 
those of the main series, so that near the limb only one series of 
bundles is left (Arber, 1920, Fig. 28 e). In the limb there is no 
differentiation of the mesophyll into palisade and spongy parenchyma, 
and there is only one series of bundles to be seen, but the phloem is 
