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1898 | REGENERATION AS EXHIBITED BY MOSSES 175 
but rather by contact. Leaves were also grown in soil with 
about the same result except that a greater number of rhizoids 
originated from the surface of the leaf nearest the air. The 
formation of buds upon the leaf in the ordinary manner was 
naturally prevented and when the rhizoids reached the surface of 
the soil and were exposed to light, they gave rise toan abundance 
of protonema-like branches and numerous buds. 
A culture of leaves with long, sparsely branched rhizoids 
which had been grown in the dark was removed to the light and 
allowed to undergo further development. When examined a 
week later the rhizoids had produced in the apical region an 
abundance of branches, part of which were still rhizoidal in 
character. A large number of the branches were, however, dis- 
tinctly protonemal, the cell-walls colorless, the cross walls per- 
pendicular, the cells short and filled with an abundance of oval 
chlorophyll bodies. The rhizoids also contained chlorophyll 
bodies but they were fewer in number and of an elongated len- 
ticular form. An enormous number of buds was also formed, 
and in one of two ways: either as a direct modification of a side 
branch from a rhizoid cell, or as a side branch from one of the 
lateral protonemal branches. This is plainly illustrated in figs. 
6 and 7. Occasionally a bud was formed later near the leaf, but 
the great majority made their appearance towards the distal 
extremity of the rhizoids. 
A question which now presented itself was: Is the continued 
exposure to light necessary to call forth the production of buds? 
In order to determine whether buds would be produced by light 
induction, leaves were grown in bright light for nearly two weeks 
and then carefully examined to see that no buds had been 
formed. They were then placed in the dark chamber and after 
five days the formation of buds was observed. The number was 
much less than from those leaves in the light, and on account of 
a lack of food material only a limited growth occurred, Whether 
this light induction is due to physical or chemical changes in 
substances already present in the leaf, or to the accumulated 
products of photosyntax, cannot be stated with certainty, but 
