Holden . — Some Wound Reactions in Filicinean Petioles. 781 
actual surface of the injured area is that they show no traces of suberization 
upon their outer walls. They are, however, usually protected to a large 
extent by the scab-like remains of the cells originally injured when the 
wound was made, and it would appear that this has proved adequate. The 
brown appearance of the wound scar in most cases is due very largely 
to the remains of these tissues, though in the few petioles where suberization 
occurs the same effect is produced. 
Immediately below the meristem proper there is a marked change in 
the character of the cells, which are much larger and possess abundant, 
coarsely granular contents. It will be seen that the most peripheral of 
these, that is, those which lie next to the cambial tissue, have also, in many 
cases, elongated somewhat, and have divided by a transverse wall suggesting 
an incipient attempt at cambium formation. 
The features upon which I should like to lay emphasis in these 
specially active forms is, first, that there is an actual production of a com- 
plete pad of healing tissue, formed by the elongation and division of the 
cortical parenchyma, and second, that there is no evidence of the secretion 
of gummy matter in any of these species during the earlier stages of re- 
action. 
It is a singular fact that the forms which exhibit the most successful 
attempts at the production of a healing tissue should be those in which 
the formation of bulbils for vegetative propagation is a characteristic 
feature. 
It would seem that the production of these structures must necessitate 
the retention of a particularly mobile and responsive type of tissue, and 
this view receives strong support from the evidence afforded by the results 
obtained in other, non-bulbiferous, species of the same genera, in other soft- 
bodied forms, and by the nature of the response to injury in the maturer 
parts of the petioles of the same forms. 
The young plantlets raised from the bulbils do not possess this power 
of regeneration to anything like so marked an extent as do the mature forms. 
In their case, in fact, an elongation of the cortical cells in the region 
affected, and the occasional division of these by a single transverse wall, 
suggesting cambial possibilities, seems to be the extent of their powers 
(PI. LXXIII, Fig. 2). 
This evident contrast with the bulbil-producing petioles also lends 
strong support to the view that the cambial activity and the formation 
of reproductive buds are correlated, since the immature forms lack this 
power. 
The elongation of the cortical cells, and their subsequent division to 
produce two or three daughter cells, would seem to be the most general 
type of response, and is a feature of the majority of the remaining forms 
examined. Thus in Lastraea Filix-mas , in Poly podium glaucum , and in 
