Holden . — Some Wound Reactions in Filicinean Petioles . 791 
dilatation of the petiole, and the formation of a distinct intumescence by the 
irregular division of the infected cells. 
12. Where cell-elongation occurs, pathogenetic, amitotic nuclear division, 
either complete or incomplete, may accompany this. 
13. The epidermis in the most active species may show sliding growth 
comparable to that exhibited by the cortical cells, but usually, beyond 
an abundance of gum and an increase in the size of the cells, little sign 
of activity is shown. 
14. The ceils of the endodermis either enlarge or elongate, and may 
divide so that their identity as a definite layer is lost on the side nearer the 
wound, when this approaches the bundle at all closely. 
15. There is some evidence that the phloem and xylem, when young, 
are influenced by wounding, and elongate towards the seat of injury. 
In conclusion, the author’s thanks are due to Professor Weiss for much 
encouragement and help; to Professor Carr, in whose department the major 
portion of the work has been done, and who has permitted his plant-house 
to be used for the experimental work ; to Mr. S. Garside, M.Sc., lately of the 
Victoria University, Manchester, who kindly collected and preserved part of 
the material used ; and to Miss Bancroft, B.Sc., who performed a series 
of control experiments on a number of the hardier forms, whilst studying at 
the University College, Nottingham. 
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