GROUPING OF SPECIES. 85 



agreeing in one characteristic, differ considerably among themselves 

 in other respects, especially in the shape of the leaves. None of these 

 species have permanently opposite or stemless leaves. 



Leaves of seedlings hairy : Eucalyptus calophylla, E. citriodora, E. 

 coriacea^ E. eugenioides, E. macrorhyncha, and E. 2)anicidata. 



Leaves permanently horizontal, darker above than below: Eucalyp- 

 tus hotryoides, E. caloi?hylla^ H. corymhosa^ E. diversicolor, E. resini- 

 fera^ E. rohusta, and E. saligna. The foregoing species being all indig- 

 enous to the moister regions of Australia, the characteristic placing 

 of the leaves vertically is not necessary. A few species, including 

 E. corynocalyx, E. diversicolor , E. pihdaris, and E. punctata, while 

 not having their leaves so distinctly permanently horizontal, have 

 leaves with the two surfaces more or unless unlike. 



FLOWERS AND SEED CASES. 



Flowers coumionly in threes: Eucalyptus leuco.ryloii, E. longlfolia^ 

 E. lu'miiudis. 



Flower clusters borne on a distinctly flattened stalk: Eucalyptus 

 hotryoides, E. gomphocephala^ E. goniocalyx, E. occidentalism E. punc- 

 tata, E. resinlf era, and E. saligna. 



Flower-bud covering long and prominent: Eucalyptus cornuta, E. 

 marginata, E. occidentalis, E. sideropJdoia, and E. tereticornis. 



Seed cases large (one-half inch to li inches in diameter): Eucalyptus 

 calop>hylla, E. corymlosa, E. globulus, E. gomplwcepjhala, E. longifolia, 

 E. marginata, and E. rohnsta. 



Seed cases very small (one-tenth to one-sixth inch in diameter): 

 Eucalyptus crehra, E. micvotheca, E. pohjanthema, and E. populifoUa. 



CLIMATIC ADAPTATION. 



In the following paragraphs an attempt is made to list species espe- 

 cially adapted to various climatic situations. It is not claimed that all 

 that may l)e grown successfully in any one region are listed, but it is 

 thought that the more promising ones are included. 



Adapted to hot, humid regions: Eucalyptus lotryoldes, E. calophyUa, 

 E. citriodora, E. cornuta, E. marginata, and E. resinifera. Of the 

 above, E. hotryoides, E. citriodoi'a, and E. resinifera are the most 

 likely to thrive in America and to produce useful timber. 



Adapted to warm, moderately humid regions having light winter 

 frosts: Eucalyptus amygdalina, E. hotryoides, E. cornuta, E. corym- 

 losa, E. corynocalyx, E crehra, E. diversicolor, E. globulus, E. gompho- 

 cephala, E. goniocalyx, E. occidentalis, E. rohusta, E. rostrata, E. rudis, 

 E. sideroxylon, E. tereticornis, and E. viminalis. Of the foregoing, E. 

 hotryoides, E. diversicolor, E. glohidus, E. gomphocephala, and E. tereti- 

 cornis seem best adapted to American climatic conditions, and most 

 suitable for producing timber valuable for commercial purposes. 



