382 MR. T. W. WOODHEAD ON THE 
is seen at the tip, which turns yellow and gradually extends to 
the base. Eventually it is cut off by a thin line of cells with 
corky walls, and thus decay below the abciss-layer is arrested. 
In the meantime its base has become swollen with reserve 
materials and forms a bulb-scale, the contents of which are 
practically unfreezable. With the means at my command I was 
unable to secure the freezing of these cell-contents ; this is a 
feature of some interest in species producing leaves and flowers 
at such an early season. Comparatively few observations seem 
to have been made on the abciss-layer of Monocotyledons, but 
the details in Scilla agree very closely with those observed by 
Parkin (77) in leaves of Narcissus, Galanthus, and Leucojum. 
As I have previously shown, the bulbs of Scilla are often 
curiously elongated, and a number of experiments have been 
carried out and observations made with a view to determine 
their fate. The results of one series of experiments are illus- 
trated in fig. 48, which shows three bulbs in three stages of 
Fig. 43. 
A, B, C. Three elongated bulbs of Scilla, March 2nd. 
D, E, F. The same bulbs as they appeared on April 11th. 
G, IL, I. Ditto on April 26th. 
development. <A, D, & C represent their appearance at the 
commeneement of the observations on March 2nd. "These were 
placed in moist cocoanut fibre and examined at short intervals. 
By April llth, changes indicated at D, E, F had occurred. 
