77 $ Holden . — Wound Reactions in Filicinean Petioles. 
Weiss ( 36 ), who regards the abnormal proliferation in a Stigmarian rootlet, 
described by him, as due to a fungal attack. 
The writer was fortunate enough to discover a case of superficial 
wounding in a Medullosean petiole, which had been repaired by the produc- 
tion of a typical wound periderm ( 14 ), and this led to an investigation of 
the reactions of Filicinean petioles to wounding, with a view to ascertaining 
whether similar phenomena were exhibited by these. 
An incidental study of two cases of surface wounds in Cycadeati 
petioles, those of Cycas circinalis and Bozvenia serratida , was also made in 
connexion with the present paper. These both showed the same type 
of response as the 1 Myeloxylon ’ referred to, having to the outside a layer 
of dead, excised cortical tissue, immediately below which was a band of 
suberized cells, devoid of contents, and finally a mass of cambiform cells 
which merged into the typical cortical parenchyma (PI. LXXIV, Fig. si). 
Methods. 
The investigations were commenced in the summer of 1909 at Man- 
chester, where, owing to the kindness of Mr. Garnett, of Whalley Range, 
I was enabled to perform a preliminary series of experiments in his fern- 
house. I should like to express here my appreciation of his unfailing 
courtesy, and my thanks for the facilities he granted me during the earlier 
portion of the work. Further series of experiments were performed during 
the spring and summer of 1910 and 1911, and a considerably increased 
number of forms was examined. 
For purposes of investigation the petioles, where possible, were divided 
into three regions, as follows : (i) the curled apical portion, (ii) the region 
of pinna insertion, (iii) the region below pinna insertion ; where special sterile 
and fertile segments occurred, as in Osmunda regalis and Allosorus crispus , 
both segments were examined. 
It was thought that the nature of response would in all likelihood 
differ in the still actively growing apices and the maturer parts below, and, 
as the former did not appear to have been investigated in this connexion, 
would possibly reveal some points of interest. 
The wounds were made with a sharp scalpel in each of the regions 
indicated, and were of a purely superficial nature, a thin shaving being 
removed which penetrated below the sub- epidermal layer of sclerenchyma 
characterizing most fern petioles, but did not seriously disturb the vascular 
supply. In those cases where the vascular supply was, accidentally, inter- 
fered with to any appreciable extent, it was found that various parasitic 
Fungi and Bacteria caused the complete rotting of the injured member, thus 
rendering it of little use for further study for this purpose. 
The petioles thus wounded were allowed to continue growth for periods 
varying between a fortnight and fifteen weeks, and were then cut and at 
