Jeffrey. — The Wound Reactions of Br achy phy llum. 391 
The question here arises, why the living Araucarineae and their nearest 
fossil allies should differ so strikingly in the structure and wound reactions 
of their wood from Br achy phy llum , and why the latter should resemble so 
strongly in its traumatic phenomena that very ancient coniferous order the 
Abietineae. In this connexion it is apposite to point out, that the differ- 
ences in the nature of the wound reactions obtaining between Brachyphyllum 
and existing Araucarineae are precisely the same as those which exist 
between the genus Sequoia and the remaining cupressinoid Conifers. The 
author has shown, that in both living and extinct species of Sequoia 
resin-canals are commonly formed as the result of injury, while such a 
reaction does not take place, so far as our present knowledge goes, in other 
cupressinoid genera (The Comparative Anatomy and Phylogeny of the 
Coniferales, pt. I. The genus Sequoia ; A fossil Sequoia from the Sierra 
Nevada). It is important too in this connexion to note, as the writer has 
done {op. cit .), that in the living Sequoia gigantea , resin-canals, although 
occurring only as the result of injury in the older wood, are found normally 
in the first annual ring of branches zvhich bear the cones male ana l female, as 
well as in the woody axis of the female cone. In S. sempervirens resin-canals 
appear only as the result of injury. The condition of affairs found in the 
cupressineous genus Sequoia is paralleled in the Abietineous genera Abies 
and Cedrus , which resemble Sequoia in the normal absence of resin-canals 
in the older wood, for here too in Abies magnifica and Cedrus Libani resin- 
canals occur as a normal feature of the zvoody axis of the cone as well as the 
result of injury to the wood, while in most of the remaining species of 
these genera they occur only as the result of injury to the shoot organs. 
In the genera Sequoia, Abies, and Cedrus , as the writer has indicated in the 
works already cited, the normal occurrence of resin-canals in such regions 
of vestigial persistence as the woody axis of the female cone and the first 
annual ring of branches and roots (not, however, in the roots of Sequoia ) 
is good evidence, taken with other data, which need not be mentioned here, 
but which are recorded in the articles cited above, that the resin-canals 
in question are an ancestral feature of the wood. In Sequoia sempervirens , 
Cedrus atlantica , and Abies balsamea, the resin-canals no longer occur 
normally, even in the reproductive axis, but appear only as the result 
of injury. 
The very constant occurrence of resin-canals as the result of injury 
in the genus Br achy phy llum, in several species of somewhat extended 
geographical and stratigraphical range, apparently calls for some explana- 
tion, in view of the great constancy of ligneous characters and the consider- 
able phylogenetic importance attached to them, by those whose familiarity 
with the structure of living and fossil Gymnosperms makes their opinion of 
value. In the case of Brachyphyllum we in all probability have to do with a 
wood in the stage of Sequoia sempervirens or Abies balsamea , for in this genus, 
