io6 Mottier .— Chondriosomes and the Primordia 
there are present small globular granules, as described above for the other 
plants. 
In successively older leaves it is quite easy to trace the transformation 
of these rods into the chloroplasts in passing from the base up into the leaf, 
and into leucoplasts, from the base of the leaf into the cells of the node 
of the stem. The series of changes into chloroplasts is almost identical 
with that described for the leucoplasts in the root of Pisnm. 
Passing into the leaf, these rods become oval, pear-shaped, or club- 
shaped, and many take the form of a hand-mirror. These various forms 
owe their existence to an increase in size and especially to the accumulation 
of an inclusion. The inclusion is starch, as can be readily demonstrated in 
the fresh leaf by the iodine test. The inclusion stains very slightly or not 
at all with haematoxylin. The starch inclusion may lie, for example, in the 
centre or in the broad, or sometimes in the narrower, end of the oval or 
pear-shaped chloroplast. Some are in the form of a dumb-bell with an 
inclusion in each end ; these are division stages. Towards the tip of the 
young leaf, and in older leaves, the vast majority of the chloroplasts are 
oval or rounded, with the other described forms intermingled. In some 
cases the lightly-stained inclusion represents the bulk of the plastid, while 
the densely-staining part appears as a narrow rim thickened at one side 
into a crescent. This can be verified in the fresh leaf by means of the 
iodine test. 
As the chloroplasts become older, the inclusion stains more densely, 
giving the chloroplast a more homogeneous appearance throughout. Many 
chloroplasts show two or more inclusions. It will thus be seen that the 
development of the chloroplast from the rod-shaped primordium corresponds, 
in a large measure, to the same in Pinns. The fully developed chloroplasts 
may undergo division as well as their primordia, division stages being 
readily observed. 
In the cells of the developing leaves, in addition to the chloroplast 
primordia, there are present numerous very small globular and rod-shaped 
bodies which do not develop into either chloroplasts or leucoplasts as 
described and figured in the foregoing for the other plants. These bodies 
are usually very numerous in cells of the leaf containing fully-developed 
chloroplasts. They are mainly globular, but many are in the form of 
delicate, short rods. They stain densely and uniformly in the cells in 
question. To these bodies I prefer to restrict the term chondriosomes in 
this plant. 
Passing from the base of the leaf into the nodal cells of the stem, the 
same transition of densely-staining, rod-shaped primordia into the leuco¬ 
plasts is seen, with the difference that the change from one to the other is 
more abrupt. The starch grains are circular, surrounded by a very thin 
layer of the plastid, which, however, may be widened at one side, appearing, 
