200 TUMOURS OF EUCALYPTS AND ANGOPHORAS, 



A little later, Mr. Tepper, of Adelaide, offered another ex- 

 plaiiation of if*^ — ''Eucalyptus oleosa is a species with an under- 

 ground rootstoek, from which numerous small stems, generally 

 crooked and semi-sarmentose, spring. When these are destroyed 

 by fire, &c , a host of fresh ones spring up from the caudex." 

 But no details are given of the characters of the supposed root- 

 stock. 



We owe to Mr. N. B. McKayt an interesting description 

 of tiie underground, composite, stem-encircling tumoui- of a 

 Mallee, even though it is incomplete, inasmucli as no particulars 

 about the shoots, or the incorporated roots are given. We have 

 looked in vain, however, for a more satisfactory one. He says 

 — '"Tlie indigenous timber-growths on the Mildura horticultural 

 areas consist, for the most part, of blue bush, 'bull* mallee, 



balar, pine, and needle-bush A well established bull mallee 



is a problem to the ordinary grubbing contractor. The butt is 

 a great flattened bulb of curly timber, sometimes 8 or 1 feet 

 through. It is set firmly into the soil, and even if all the roots 

 were cut off, the tree would stand in its place just the same, as 

 the upper growth is very insignificant compared with the base. 

 Chopping mallee out is an obvious impossibility, and, as the 

 wood is full of moisture, it would be an endless task to attempt 

 burning it out. Dynamite and rack-a-rock have proved equally 

 useless. Before, or rather behind, the traction-engine, the diffi- 

 culty disappears When all the stumps are uprooted, the 



adhering earth is knocked off, and they are readily burned." 



Three items in this are worth notice. Firstly, that the butt 

 is a " flattened '' bulb : that it is to say, it increases in size hori- 

 zontally rather than vertically, Secondly, it is a bulb of "curly 

 timber": it is not a case of a simple, localised thickenii g of the 

 stem, but results from the proliferation of cambium-tissue. 

 Thirdly, '• the wood is full of moisture" : it is a water-charged 

 tumour, because of the incorporation of water-storing roots. 



" "Remarks on the 'Manna' or Lerp Insect of South Australia." Journ. 

 Linn. Soc. Lond., Zoology, xvii., p. 109 (1883). 



t Eighth Progress Report of the Royal Commission (of Victoria) on 

 Vegetable Products, 1 890. 



