260 Boodle and WorsdelL — On the 
heretofore, is the presence in the young stem of an external 
endodermis extending round the outer limit of the cortical 
bundles and dipping beneath the furrows ; its presence was 
plainly shown on treatment of the section with strong 
sulphuric acid. 
The characteristic formation of periderm in this plant has 
been fully described by former authors. 
With regard to the structure of the seedling we have only 
to mention that in the main it agrees with the dicotyledonous 
type. 
It is a matter of interest to consider whether the anatomy 
of Casuarina affords evidence, favourable or unfavourable, 
bearing upon the systematic position assigned to the genus 
by Treub 1 . In the structure of its phloem, Castiarina shows 
no important departure from the dicotyledonous type, and in 
its xylem-elements it agrees pretty well with the Cupuliferae 
and other Dicotyledons. In the disposition of its xylem- 
parenchyma, &c., it forms a rather isolated case, but this 
would not appear to be of any fundamental importance. On 
the other hand, the resemblance of the wood-structure in 
Casuarina to that of the Cupuliferae is of some importance, in 
the light of the researches of Miss M. Benson 2 on the repro- 
duction of the Amentiferae : but this importance is much 
diminished by one or other of the characters of agree- 
ment occurring in the wood of Rosaceae, Saxifragaceae, 
Cornaceae, &c. 
The chief result of our examination of Gnetum has been 
the establishment of the fact that the wood possesses two 
kinds of vessels, viz. those of the primary and early secondary 
wood, with several perforations, or with a long, narrow, single 
perforation, and those so well known in the secondary wood, 
with a single round perforation. 
Still more important, perhaps, is the structure of the node, 
1 Treub, Sur les Casuarinees et leur place dans le Syst. Nat., Annales du Jard. 
Bot. de Buitenzorg, X, p. 145. 
2 Benson, Contributions to the Embryology of the Amentiferae, Linn. Soc. 
Trans., 1894. 
