446 MR. POTTER ON DEVELOPMENT OF STARCH-GRAINS IN 
and glycerine, and showing the vascular system of three leaves; the 
cauline cortical bundles have hardly begun to make their appearance. 
x 20. 
Fig. 2. Section through the periphery of an older stem, showing the connexions 
of the five bundles of a single leaf-trace (x, y, z) and their position 
relatively to the cortical bundles, a a. X 3. 
Fig. 3. A similar section, showing in addition the irregular cortical bundles, 
the course of which was not followed. 
Fig. 4. Thick transverse section of a stem; the parenchyma has been partly 
dissected away, and then made transparent with potash and glycerine. 
Fig. 5. View from without of a small part of the system of cortical bundles of 
an old stem which had lost all the soft parenchyma by rotting. The 
dotted lines indicate the position of the leaf-scars relatively to the 
bundles. : 
Fig. 6. View of the diamond-shaped leaf-scars from without, showing the five 
bundles of each leaf-trace; behind is drawn a diagram of the net- 
work of bundles of the cortical system ; the arrow shows the direction 
of the main axis. 
Fig. 7. Transverse section of a single circular group of cortical bundles; the 
parenchyma at the periphery is pressed out of shape by the increase 
in bulk of the group of bundles, x20. 
Fig. 8. Longitudinal radial section of stem, showing the relative positions of 
bundles of leaf-trace (x, y, z), cortical bundles (a), and the normal 
ring (r). x 20. 
———— 
On the Development of Starch-grains in the Laticiferous Cells 
of the Euphorbiaces. By M. C. Portzr, B.A., St. Peter's 
College, Cambridge. (Communicated by Dr. S. H. VINES, 
F.L.S.) 
[Read December 20, 1883.] 
Tur Euphorbiacee are characterized by possessing numerous 
laticiferous cells in the ground-tissue of their stems and leaves; 
these, in addition to containing latex, also contain large quan- 
tities of starch-grains, peculiar and irregular, known as rod- or 
bone-shaped. These grains appear to have been first observed 
by Meyen* about the year 1836. 
As regards the formation of starch, Crüger t says :— 
“All starch-grains come from the protoplasmic layer, which 
lines the inner wall of the cell as long as it is capable of deve- 
lopment, and as long as protoplasm exists in the cell. In all 
starch-grains where the layers are distinctly formed, and à 
* ‘Ueber die Secretions-Organe der Pfianzen:’ Berlin, 1837. Schleiden's 
‘Principles of Botany,’ p. 20. 
t “ Westindische Fragmente, Drittes Fragment," Bot. Zeitung, 1854. 
