STUDIES IN PLANT REGENERATION 211 
REGENERATION IN LEAVES 
Leaves are organs which usually upon removal from the plant, 
without further incisions, are freed from connection with preformed 
rudiments. A few (Bryophyllum crenatum and Leptaxis Menziesit) 
have normally such primordja, which had to be detached before 
the leaves could be included in the limits of the present work. 
Besides a repetition of the experiments with normal leaves as 
wholes and in parts, the behavior of modified leaves of different 
types has been investigated; among the latter figured thorns, 
phyllodes and so-called “juvenile” leaves. Іп connection with 
the regeneration of the bean leaf, an anatomical study of callus 
and root-formation in this species was undertaken ; and, finally, 
the power of Leptaxis Menziesii to replace its bud after its removal 
has been re-examined. 
Of eighty-two species of green leaves used as cuttings only a 
very small proportion needs recording. The majority conform in 
their method of producing root and shoot — or, more often, the 
former only, to the descriptions given everywhere in botanical 
literature.* Véchting,+ in his discussion on the behavior of these 
organs, expressed the opinion that the leaf in which the power to 
regenerate a new plant is lacking, would, upon investigation prove 
to be the exception, rather than the rule. This has not been borne 
out by the following experiments. In all of the sixty-one species 
which gave any positive results, roots were formed, while only 
twelve kinds gave rise to shoots. All of the latter, with the ex- 
ception of Piper canescens had been known before to have this. 
property, so that out of 71 species in which the regenerative power 
had not been recorded, only one was discovered which was able to 
produce a new plant. 
In 1816, Knight f planted in earth the leaves of the potato, 
expecting them to root and to form tubers at the base. Не was 
surprised that neither of these things happened, but that He man 
the petiole swelled up, and was found to contain material like that 
in the tuber. (Erp. 33.) Consequently the ease and MET 
* For literature see Vóchting /. с. 92 520. 
uA уа | ES 
18 g Knight, T. On the action of detached leaves of plants. Phil. Trans. 289. 
16. 
