216 TUMOURS OP EUCALYPTS AND ANGOPHORAS, 



to fuse at all on one side. Encircling tumours, as they grow 

 downwards, may progress faster on one side than on the other. 



If the nodules do not develop promptl}-, while the tissues are 

 quite young, that is, if the period of incubation is longer than 

 usual, the nodules seem to make slower progress, when they do 

 appear. Meanwhile, the lower internodes may have lengthened 

 to such an extent that the concrescence of pairs may be delayed 

 or even prevented. Angophora seedlings frequently oflfer very 

 characteristic examples of this kind of thing. 



The E. sideroxi/lon-series (PI. v., lower row, and Pis. xiii.-xvii.), 

 of which the earliest, the last, and as many intermediate stages, 

 as space will allow, are shown, are intended to indicate the course 

 of events in a susceptible species, W ith the exception of the 

 tumour in PI. xvii., all the photographs were taken when the 

 specimens were fresh. They are variously reduced, from about 

 one-third to one-half, or even more in the larger ones. They are 

 intended to show the composite tumours, with recognisable por- 

 tions of the seedling-stems and tumour-shoots, and, especially, 

 various stages in the capture of lateral roots. 



The smaller of the two crossed seedlings (PI. xiv., fig.2) shows 

 the first and second fused pairs of nodules concresced; the third 

 pair have not yet completely fused; one nodule from the fourth 

 pair is missing. 'Ihe growing-point was injured. The taproot 

 is caught between a lateral root and the tumour, so that it can- 

 not be freed without trimming the latter. There was enough 

 soil between the two tumours to prevent fusion. The larger 

 specimen has lost its seedling-stem, and two of the tumour-shoots, 

 one on each side, are taking the lead. No roots had been 

 incorporated in either specimen. 



The seedling in PI. xiii., fig. 1, with a stem-height of 20 inches, 

 has three pairs almost completely concresced, and two pairs not 

 yet fused. Two roots are just incorporated, and another was 

 ready to be. 



The two seedlings on the right (PI. xiii., tig. 3) show incom- 

 plete concrescences at the top; and an early stage of the incor- 

 poration of a root. 



Fig.2 of the same Plate (reduced by nearly one-half; is a fine 



