320 



2. Western Australian forms with the characteristics of the Erenisean plants of the southern half 

 of Australia, e.g., E. calycogona, E. gracilis, E. uncinata, E. oleosa, E. dumosa. E. uncinata stands rather 

 isolated in Western Australia, and shows only slight polvmorphy; the other species, however, are rich 

 in forms also in the west, where evidently some forms have become independent and developed into very 

 characteristic forms (E. salubris and others). 



3. Western Australian species, which are distinctly connected with certain east-Australian forms, 

 e.g., E. marginata, which, with E. patens, E. Todtiana, and E. buprestium, represent a group of the genus 

 otherwise not developed in Western Australia. 



4. Western Australian forms which have no connection with eastern forms, but are greatly developed 

 in the west. This refers specially to the series Cornutse of Bentham and the genetically allied E. redunca- 



5. Western Australian forms which are geographically isolated, and have. also in Western Australia 

 only a single or few forms. In this group we must include, at least, at the present state of our knowledge t 

 a considerable number of species. To it belong not only species of the Western Australian interior, as 

 E. piriformis, E. tetraptera, with E. Forrestiana, E. Preissiana, E. tetragona, with E. eudesmioid.es, but also 

 important species of the south-west coast region, e.g., E. calophylla with E. ficifolia, E. diversicolor, 

 E. gomphocephala, E. erythrocorys. The further relations of these species are mostly quite uncertain, but 

 in some one can notice faint relations to north- Australian types. 



In the systematic-geographical relations of the Eucalypts of Western Australia the whole flora is 

 reflected in manifold ways. We know, unfortunately, at present, so little of the morphology of this most 

 important genus that it would appear idle for us to make guesses as to the origin and development of the 

 Eucalyptus Flora of Western Australia. 



The geographical distribution of the species of Eucalyptus within Western Australia calls for a few 

 remarks, because it shows some remarkable anomalies, which can be expressed in the following sentences : — 



1. Great scarcity of species from about 30 deg. south latitude to the northern limit (except on the 

 west coast, where the scarcity commences at about 27 deg. south latitude). In this region one meets 

 generally only the pan- Australian E. rostrata on the watercourses. 



2. Greater number of species south-east of the Eremsean area. This flora has been explored only 

 recently, and probably incompletely ; it is distinguished by very characteristic forms derived from typical 

 Eremsean forms of wide range (E. oleosa, E. gracilis, E. dumosa, &c). 



3. Very great number of species in the interior south-west region. The south-east dominates in 

 this category. The Eyre district contains the greatest number of species, the Stirling district not many 

 less. This is the rich Eucalyptus Flora already discovered by Drummond and further explored by Maxwell, 

 which extends to the east from the Stirling Range. The flora diminishes towards the north, but the limits 

 are not yet known. The Avon district shows a great decrease, but gains a very characteristic endemic 

 form in E. macrocarpa. 



4. Smaller' number of species in the forest region of the south-west, which are, however, very 

 gregarious and systematically very independent. Former papers ( (1) on p. 436) give a full account of this 

 economically very important group, and its division into the zones of E. diversicolor and E. marginata, 

 with the addition of E. calophylla and the alluvial species. 



5. Peculiar species of the littoral calcareous zone (coast limestone region). E. gomphocephala (in 

 the Darling district) and E. erythrocorys (in the Irwin district) are systematically the most independent 

 of all Western Australian Eucalypts. 



Locality. — -The genus Eucalyptus is the most important arborescent genus in Western Australia, 

 just as it is in the greatest part of Australia. Soil and moisture determine their feature in the landscape. 

 E. rudis and E. patens are the most important species to be met on the alluvial lands of the south-west ; 

 they are just as characteristic on the extensive lowland alluvials as in the narrow valley-like depressions of 

 the uplands. Both species are hardly gregarious ; their forests often give a park-like appearance to areas. 



The granite country of the south-west region is the home of the three most important forest-forming 

 Eucalypts of Western Australia, as mentioned above. E. diversicolor (Karri) and E. marginata (Jarrah) 

 form the densest forests. Both exclude other species to an essential amount, except on the borders of 

 the region, and in places where local geological changes have taken place other Eucalyptus species 

 intermingle with them, especially E. calophylla. E. redunca (Wandoo) forms much lighter forests. Tha 



