1918] RECORD—RESINOUS TRACHEIDS 67 
mally, as in severe wounds. The low vitality of the ray and wood 
parenchyma at that stage may be considered responsible for the 
excessive amount of waste matter produced, some of which finds its 
way or is excreted into the cavities of the adjacent cells. 
The parallel between the gymnosperms and angiosperms in 
the manner of their disposal of secreted or excreted products in 
the xylem extends further. Pinus, Picea, Larix, and Pseudotsuga, 
for example, have vertical resin canals in the wood. Similar 
canals are normal to the secondary woods of nearly all genera of 
Dipterocarpaceae and of Copaifera, Daniellia, Eperua, Kingioden- 
dron, Oxystigma, Sindora, and Prioria of the Caesalpineoidae. Ver- 
tical resin canals arise traumatically in Abies, Sequoia, Tsuga 
heterophylla, and others; similarly canals may be produced by 
injury in Liguidambar, Styrax, Terminalia, Drimycarpus racemosa, 
etc. Resin canals in the medullary rays occur normally in Pinus, 
Picea, Pseudotsuga, and Larix; similar canals have been observed 
by the writer in representatives of 11 genera of Anacardiaceae and 
2 of Araliaceae,? and others have reported traumatic canals in both 
planes in Liguidambar and Styrax. 
The writer concludes that resinous tracheids in gymnosperms 
find numerous parallels in the angiosperms, that they represent 
one form of reservoir for excretions, and that the form of the resin 
masses is in response to well known physical laws. No direct 
functional activity is attributed to the resin plates, although they 
are in certain ways analogous to tyloses and reduce the permea- 
bility of the wood. 
As a diagnostic feature resinous tracheids appear of value in 
Pinus albicaulis and may prove to be so in other cases. 
YALE UNIVERSITY 
ORD, SAMUEL be Intercellular canals in dicotyledonous woods. Jour. 
Paani periann 19 
