RESEARCHES ON THE DEVELOPMENT OF STARCH-GRAINS, 29] 
REsFARCHES upon the DEVELOPMENT of STarcH-GRAINS. 
By A. F. W. Scuimper. (Pl. XIX.)! 
1. Tue formation of starch-grains in chlorophyll-corpus- 
cles was investigated first by Nageli® and then by Sachs,? 
and the conclusions arrived at were the same in both cases. 
Both observers directed their attention principally to the 
leaves of flowering plants, but Nageli further observed the 
green ground-tissue of the stems of certain Cacti and also 
the Characez. According to their accounts, which are essen- 
tially the same, the starch-grains are formed, either singly or 
several together, at various points in the chlorophyll-corpus- 
cles; they then increase in size, and where several are 
present, they become flattened along the planes of contact. 
The chlorophyll-corpuscle also increases in size at first, but 
it subsequently diminishes, and it frequently disappears more 
or less completely. 
Ican confirm the results of these observers as regards the 
material which they used. This mode of the formation of 
starch appears to be universal in the mesophyll, and it 
occurs also in the green portions of the stems of many, but 
not of all phanerogamous plants. The mode of the formation 
of starch-grains in the stems of some plants differs con- 
siderably from that which has been described. In these 
cases the starch-grains do not originate at any indefinite 
points in the chlorophyll-corpuscles, but always just beneath 
their free surface (figs. 4,6, 9). The thin layer of the chlo- 
rophyll-corpuscle which covers the starch-grains is soon rup- 
tured, and the grains then project. ‘They frequently appear 
to be quite superficial from the beginning. 
If the chlorophyll-corpuscles are spherical and not 
flattened, starch-grains may originate at all points of the 
peripheral portion. If, however, and this is more frequently 
1 This paper was published in the ‘ Botanische Zeitung’ for 1880, 
No. 52. The author had no opportunity of seeing the paper by Dehnecke 
on a similar subject, which was published earlier in the year, ‘ Ueber 
nicht assimilirende Chlorophyllkorner” (Diss. Inaug. Bonn.,’ 1880). 
Dehnecke shows that starch-grains may be formed in chlorophyll-corpuscles 
otherwise than by assimilation. 
+ ‘Zeitsch. fiir wiss. Bot.,’ Heft iii u. iv; ‘ Die Starkekérner,’ p. 398. 
> “Ueb. den Hinfluss des Lichtes auf die Bildung des Amylums in den 
Chlorophyllkérnern,” ‘ Bot. re 1862; “Ueb. die Auflésung und 
Wiederbildung des Amylums in den Chlorophyllkérnern bei wechselnder 
eae eee ‘Bot, Zeitg.,” 1864; ‘ Experimental Physiologie,’ 
S. 3 . 
