BY J. J. FLETCHER AND C. T. MUSSON. 199 



But the stem-nodules, as well as the composite tumours to 

 which they give rise, are complex tumours, composed of both 

 somatic cells and germ-cells ; and the latter are totipotent, 

 because in the persistent composite tumours of the Mallees, the 

 tumour-shoots complete their growth, flower and fruit, and pro- 

 duce seed. Even in the Non-Mallees, if the seedling-stem is lost, 

 two tumour-shoots may take its place, attain to tree-size, and 

 flower and fruit. But they do not prematurely disclose their 

 embryonic possibilities, in the way that some of Erwin Smith's 

 artificially produced monstrosities did. Also the production of 

 these tumours in Eucalypts under natural conditions is a matter 

 of long standing. The Mallee Scrubs, which must have been 

 the developments of centuries, were in their prime, when civilised 

 man first saw them, nearly 101 years ago. 



We may next briefly review the Australian contributions to a 

 solution of the problem we are interested in. 'Jhese relate 

 chiefly to the Mallees. The earliest descriptions of the make-up 

 of these curious plants, by Allan Cunningham,* Tenison-W oods,t 

 and Baron von Mueller,! are subject to the drawback that, when 

 these botanists visited the untouched Mallee-Scrubs, there was no 

 o])portunity of seeing uprooted plants. Two of the Baron's de- 

 tinitions will suflfice. Under E. oleosa (Dec. vii.) : " Shrubby or 



somewhat arborescent It is this species which forms a 



large ingredient of the ' Mallee-Scrub,' constituting tall bushes 

 branched from the root." Under E. striata (Dec. x.): ".Shrubby 



or somewhat arborescent ; habit that of the Mallee-Euca- 



lypts, with many stems from one root." 



Mr. J. Ednie Brown, § in 1882, gave his interpretation of the 

 " root " of the Mallees, from whicii the stems are said to rise, as 

 "being apparently a kind of dwarf trunk, the stems of our de- 

 scription [under E. gracilis. "A Mallee tree with several stems"] 

 representing its branches." 



* Oxley's Journal (in the entry for June 10, 1817), p.63 (1820). 

 t ''Geological Observations in South Australia,"' p. 83 (1862). Also, 

 Proc. Linn. Soc. N. S. Wales, vii., p. 566 (1883). 



X "Eucalyptographia," under the various Mallees (1879-84). 

 § Forest Flora of South Australia, Part v. (1882). 



