804: A, F. W. SCHIMPER. 
beneath the cork, contain, according to Wiesner,! etiolin- 
corpuscles which become chlorophy!l-corpuscles under the 
influence of light. These bodies, which are really starch- 
forming-corpuscles, and which, as in all other cases, pro- 
duce no starch in the cortical cells, become converted, as far 
as I could observe, into very small and only slightly 
coloured chlorophyll-corpuscles, whereas those which are 
situated in the more internal cells and which contain starch- 
grains become converted into large and brightly coloured 
chlorophyll-corpuscles. When the contained starch-grains 
are very small they undergo complete absorption. In the 
still more internal parts of the tuber, where the starch-grains 
are very large, the starch-forming-corpuscles are reduced to 
a small gelatinous residue, they can naturally only become 
delicate ill-defined chlorophyll-corpuscles. 
These facts can be very readily made out in the rhizome 
of Canna (figs. 5|0—53) ; here, in correlation with the form 
of the starch-forming-corpuscles, the chlorophyll-corpuscles 
are sickle- or spindle-shaped (spherical in the outer cells) 
and contain crystalloids. 
The investigation of the following gave the same results ; 
the rhizome of Iris florentina, of Costus Malortieanus, the 
scales of a Trevirania, the roots of Gunnera scabra, and of 
Phaus grandifolius, which resemble the tubers (fig. 45). 
Not all starch-forming-corpuscles, however, are capable of 
being converted into chlorophyll-corpuscles, even when 
their whole development goes on in the presence of light 
(epidermis of Philodendron and Phajus, endosperm of 
Caryophyllee). 
It is evident, from what has been stated above, that there 
is a complete resemblance between starch-forming-corpus- 
cles and leucophyll-corpuscles, and even with chlorophyll- 
corpuscles in their first stages of development; the question 
naturally suggests itself as to whether or not these cor- 
puscles are identical. The only obvious difference between 
them is the former can produce starch-grains from assimilated 
substances, whereas the latter cannot produce any starch 
at all, so far as is at present known. 
A more careful investigation shows, however, that even 
this difference is by no means constant; and that, on the 
contrary, these corpuscles completely resemble each other in 
this respect also. 
It is well known that the mesophyll of etiolated plants, 
which have not yet exhausted their reserve materials, con- 
tains no starch, although it is present in quantity in their 
1 Wiesner, ‘ Uester. Bot. Zeitschr.,’ 1877. 
