PHYSIOGRAPHY OP THE AUSTRALIAN ALPS. 373 



■Contrasting the orders richest in species we find : — 



Australian Alps. Australian Alps and Tasmania. 



(Restricted.) (Endemic in both regions.) 



Compositte...5 genera and 8 species. 8 genera and 14 species. 



In a paper on the Phanerogamia of the Mitta Mitta* F 

 suggested that meteorological conditions would probably be found 

 to liave exerted a dominating influence in the evolution of 

 varieties of phmts. Further observations not only tend to confirm 

 tliat suggestion, but point to the probability of physical causes 

 prevailing over geological causes of distribution, or in other woi'ds 

 sub-aerial influences being the most important factors in plant 

 distribution. 



It would be impossible, within the scope of this paper, to deal 

 satisfactorily with the facts which lend support to this theory. 

 The evidences may form the subject matter for another paper for 

 the Association at some future time. 



Remarks on the most jn'evcdent Genera. — The extensive orders 

 Compositae and Leguminosai first claim attention as being the 

 richest in species. Bentham remarks,! "that the Compositae are 

 the most extensive of flowering plants, and represented in every 

 quarter of the globe in every variety of station," and that there 

 are five hundred species indigenous to Australia. I have noted 

 great variation in the growths of many composite herbs in the Aus- 

 tralian Alps during different seasons, sports being abundant in dry 

 seasons, and the reversion to foliaceous growths very remarkable. 

 I have observed the florets in Mia-oceris Fursteri becoming pedi- 

 cellate and assuming the form of an Umbellifer. Among Com- 

 positte, such as Brachycome, Aster, Senecio and HelicJivysum are 

 most abundant, Brachycome by the herbaceous species B. decipiens, 

 B. diversifolia, ifec, which yield a fine carpeting of flowers on the 

 open grassy ridges and flats during early summer, ascending to 

 the alpine regions at the higher plateaux — ^6,000 feet elevation. 



Aster includes, among other arboreous forms, the evei'-scented 

 Native Musk {A. a7'yoj)Jiyl/ns), which attains its greatest luxuriance 

 among the deeply-vegetated and shaded glens on the sub-alpine 

 littoral slopes where humidity prevails. 



Shrubs as A. stelluhita, A. uiyrsinoides, are more evenly dis- 

 tributed in open northern areas along the banks of streams, 

 although the latter is represented by dwarfed forms on the lower 

 ridges of the higher plateaux. Such herbs as A. Celmisia are 



* Phanerogamia of the Mitta Mitta. Trans. R. Soc. Victoria. 

 + Flora Australiensia, Vol. iii, p. 449. 



