appearance to that of the outermost layers of the cortex. In 

 one experiment a fragment some 1 x 1 x "5 cm. from the 

 investing layer of resin near the base of the trunk was treated 

 with alcohol and all the resin removed. The residue was a 

 solid mass of cellular structure the size and shape pf the 

 ■original fragment. Many of the thin flakes of resin to be 

 found between the leaf bases in the upper region of the stem 

 also showed fragments of cellular structure. 



A small feature of additional interest has been found in 

 examining these residues. In many cases, in addition to the 

 ■cortical cells of the stem, there was present a greater or less 

 -amount of a thin septate fungus mycilium. No sign of spores 

 or fructification has been noted, but it appears as if the 

 fungus was saprophytic upon the dead leaf bases or even upon 

 the cells occluded in the resin. 



In further confirmation of the hypothesis that the resin 

 is, in the main, an intracellular secretion of the cortical cells 

 of the stem, a number of fragments of Kangaroo Island grass 

 tree (X. Tateij "gum," from a commercial source, was selected 

 i'or examination. It was quickly recognized that amongst the 

 fragments were two kinds, differing in appearance. The resin 

 in some cases was clear and translucent, in the other it 

 appeared much denser, almost opaque, when held up to the 

 light. The residues of samples of each kind were examined 

 as above. The translucent resin showed many cells similar 

 to those found in the resin of X. quadrangulata. The denser 

 Tesin also showed a few such cells, but in this case the bulk 

 <of the residue was a mass of almost pure fungus hyphae. 



Conclusions. 



The resin of Xanthorrhoea quadrangulata is an intra- 

 cellular secretion, principally of the peripheral cortical cells 

 of the stem. The resin so formed is moulded by pressure 

 between the persistent leaf bases clothing the stem, and, 

 at sun heat becoming viscous, flows to a certain extent, 

 destroying the original cellular matrix, but still retaining 

 fragments, as can be seen by an examination of the residues 

 of alcoholic solutions of the ''gum." It follows, therefore, 

 that there is little likelihood of any method of collecting the 

 resin other than by destroying the tree. Any method of 

 stripping the trunk, assuming one could be devised that should 

 be commercially possible, must kill the plant, since it would 

 expose unprotected parenchyma tissues to the atmosphere and 

 open the way for fungal and animal attacks. 



