98 
Mottier.—Chondriosomes and the Primordia 
in which there seems to be more than one starch inclusion. This is 
especially true in young gemmae, in certain vegetative cells of the antheri- 
diophore, and elsewhere. Such chloroplasts probably contain two or more 
starch grains or small masses of starch, and in this respect chloroplasts 
and leucoplasts seem to be alike. The nucleus (; n , Fig. 6) has a very 
delicate nuclear membrane, with the chromatin in the form of small, 
rounded granules, as may be seen also in cells of Fig. 5. Fig. 7 presents 
a cell beneath a dorsal air-chamber. In the living thallus such cells appear 
green with numerous large, well-developed chloroplasts. The chloroplasts 
here stain a deep blue with the crystal violet and present a uniform, homo¬ 
geneous structure. This is the usual behaviour of mature chloroplasts rich 
in chlorophyll. In these and similar cells (Fig. 7) the chloroplasts show 
the usual division stages. In such cells the chondriosomes likewise show 
division stages (Figs. 6 and 7). If we now turn to still older cells in the 
thallus, we have the structure presented in Fig. 8, which represents a tan¬ 
gential view of the cell. The chloroplasts are smaller and irregularly 
distributed along the periphery of the cell. The scanty cytoplasm is 
omitted from the figure. They are rounded or somewhat lenticular, as 
described above. The majority of the chondriosomes are in the form of 
delicate rods of varying length. Some seem to be dividing. In preparations 
stained with iron-alum-haematoxylin, the chondriosomes appear black, while 
with the crystal violet their colour is a beautiful deep blue. In such cells 
the chondriosomes stand out so clearly that the preparations make most 
excellent objects for the demonstration of both the chloroplast and the 
chondriosome. 
Taking the thallus of Marchantia as a whole, we find chondriosomes 
in all cells. In the apical cells and their immediate neighbours, the chloro¬ 
plasts and their primordia are small, but, as a rule, readily distinguished 
from the smaller granular or rod-shaped chondriosomes. In the isodi- 
mensional cells not far removed from the growing point, the chloroplasts 
begin to assume their adult form, being much larger. The chondriosomes 
are, however, larger and more sharply defined than at the growing point, 
but always in the form of granules or rods. Many are seen in process 
of division. Short rows of granules are found here also. In the dorsal 
chlorenchyma layer, chondriosomes are relatively few, but they are thicker 
than in deeper parts of the thallus. Those of the cells forming the floor of 
the dorsal air-chambers are relatively larger than in other cells below them 
(Fig. 7). The older cells near the centre of the thallus have apparently 
few chloroplasts, but many slender, rod-shaped chondriosomes that vary 
greatly in length, along with those that may be spoken of as very short 
rods or granules. Many of these rods and granules show constrictions in 
the middle as if in the process of division (Fig. 8). The division stages in 
younger cells present the same appearance. In much older parts of the 
