323 



We must bear in mind that wc know so little about some species that we cannot 

 say whether we shall later find that they attain a very much larger size. Dwarf species 

 only exceptionally attain the dignity of a tree from which timber may be cut. In a 

 few cases {e.g., E. redunca) the typical fornx is a shrub, wliile a variety assumes tree-form. 



Mueller touched on the difficulty in the following passage : " The characters of 

 shrubby Eucalypts proving generally less constant than those of the tall timber-trees 

 of this genus." (" Eucalyptographia," under E. occidentalis). 



Some Mallees, when they attain their best development, grow into medium-sized 

 trees, 30-40 feet being common, and a height of 50 feet not being rare, while the very 

 exceptional height oi 10 feet (measured) in the case of E. gracilis is worthy of special 

 note, and, perhaps later, of special classification. In other words, we must bear in mind 

 that the usual idea of a Mallee being a shrub may require a good deal of modification. 



When the plant consists of a number of small stems close together it goes l^y the 

 name of " Whipstick Mallee." 



Some general notes on Mallee will be found in Part IV, pp. 94, 98, of the present 

 work. For a valuable paper on the development of Mallees, see Fletcher and Musson 

 in Proc. Linn. Soc. N.S.W., xliii, 199 (1918), which is abstracted in the present work, 

 Fart XLIX, p. 284. 



There is a certain amount of convenience in a geographical classification of 

 Mallees, thus we have : — 



a. True Mallees. 



True Mallees (as originally defined), with large bulbous root-stocks. Foiuid in 

 regions of comparatively low rainfall, and in plain coimtry. 



Speaking generally, it may be said that Mallees are smooth-barked, thin-barked, 

 and bark-bound when young, and later, the outer bark falls off more or less abmidantly 

 as ribbons. As development proceeds the rough bark on the lower part of the trunk 

 becomes less ribbony, and more or less flaky and hard, till at length — at maturity, and 

 when there is no necessity for the fall of the bark — the butt becomes rough-l^arked, with 

 a dark-coloured, hard-flaky, sub-fibrous exterior. 



I shall show, under Gums, that the state of having a smooth l)ark is an ideal, 

 and it will be later proved that all groups of barks have exceptions more or less important. 

 Mallees do not escape this general law. For example, E. Camfieldi and E. lignstrinc, 

 which might ].iv some be classed with the Mallees, seem better placed under the 

 S ringyl arks. 



One must bear in mind that the typical Mallee, with its bulbous root-stock and 

 many comparatively thin stems, often arranged in a more or less circular manner, is 

 a condition arrived at as the result of environment, but the same species may be single- 

 stemmed and like an ordinary tree in appearance. This dimorphous character has 

 given difficulty to many people, who have thought that the two forms represented 

 different species. 



