226 THE. NORTH- AUSTRALIAN EXPEDITION. 



further consideration, are based upon sound principles. You will ob- 

 serve that I have, of thirty-four species, given the characteristic of the 

 bark, and of the greater part a full diagnosis ; in several cases addi- 

 tional information will be gained from my other notes, and the species 

 will, from the unarrived collection, be increased to about forty; of 

 these are only two fruticose, and a considerable number produces op- 

 posite leaves ; in the colonies of Victoria and South Australia, on the 

 contrary, scarcely a single one belongs to opposite-leaved species, whilst 

 numerous kinds are not growing beyond the size of shrubs. Tor the 

 use of the colonists the bark will always afford the best mark of dis- 

 tinction ; trees, at times, may be distinguished of various kinds, so far 

 as it is necessary for a traveller, or the practical use of the settler, in 

 telescopical distances ; nor can the monographer of these plants dis- 

 pense with the knowledge of those characters which I pointed out in 

 my cortical system ; and, as proof of this, I may state that I should, 

 from herbarium specimens alone, unhesitatingly pronounce the Silver- 

 leaved Iron-bark, the Silver-leaved Box-tree, and one of the Bathurst 

 Stringy -bark-trees, as identical ! or rather, as insignificant varieties of 

 the same species ; and yet nothing can be more striking than the dif- 

 ference in texture and structure of the bark of these three species, 

 characters which of course do not admit of vacillations. This is how- 

 ever not the place to enter upon my investigations of these interesting 

 trees, on which I hope to throw more light in a separate memoir. But 

 you will observe that the five sections, Leiophloice 9 Hemiphloice , Rhyti- 

 pkloice^ Packypkloite, Schizophloia, exhibit trees which, as Flooded 

 Gum-trees, as Iron-bark-trees, Stringy-bark-trees, etc., belong to so 

 many respective sections, and that the trees, as such, are familiar to 

 the colonists. Thus, for instance, at least six Stringy-bark-trees exist, 

 very distinct as species, which however always will pass under this col- 

 lective name by the settlers. The sixth section, " Lepidophloia " is 

 quite a botanical novelty ; it includes those Eucalypti which, techni- 

 cally, I would call Mca-trees, remarkable for a lamellar, brittle bark, 

 much resembling mica schist. The Melaleuca Gum-tree of Leichhardt, 

 and E. melismdora of Ldl., belong to this group. 



cortical system for the determination of herbarium L r , c, 



rally impracticable, 1 have added a clavis, in which I employed for the 

 above-mentioned species, after having them divided into sections some- 

 what similar to those of former botanists, an arrangement according to 



The appliance of a 



