478 EVOLUTION OF THE EUCALYPTS, 



interesting and instructive classification of tliera, according to 

 size and shape of cotyledons, could be made; and that, in many 

 instances, this tentative arrangement followed certain morpho- 

 logical and chemical lines in a manner hitherto unsuspected by 

 workers on the subject of Eucalyptology. (Certain species were 

 found to adhere to the entire type of cotyledon, and in the case 

 of the Eastern Australian Stringybarks, this adherence was very 

 close. In other instances, there seemed a return to the primitive 

 type of cotyledon, as in E. dumosa and E. incrassata. What 

 species represent the prototype of the emarginate form, whether 

 it appeared suddenly or gradually, in what part of the continent 

 it first developed, cannot at present be told. Fuller knowledge 

 of the seedlings of the remaining species of Eucalypts, and a 

 consideration of their distribution, may give a ke}^ to solve the 

 problem. However, just as we have the Corymbosas with large, 

 entire cotyledons, so we have the group, like E. marginata, with 

 large, emarginate ones: then we have the peppermint-group, with 

 smaller cotyledons, slightly or hardly at all emarginate; then a 

 large collection of species, all more or less emarginate, but with 

 cotyledons gradually diminishing in size, till we get the almost 

 minute ones of E. rostrata and E. viridis; and finally, the ex- 

 tremely bifid species of the E. squamosa type. We may thus 

 place the Eucalypts in two great cotyledonary classes, entire and 

 emarginate, and group them as follows. 



{.Entire Cotyledons. 



(a). Blood woods or Corymbosas, characterised by very large 

 or medium-sized cotyledons, usually reniform in shape, and 

 resembliiig those of the Angophoras, comprising E. calophijUa, 

 E. perfoliata, E. exiniia, E. cofynibosa, E. trachyphloia.^ E. citrio- 

 dora, E. maculata, and E. %7itermedia. The primary leaves very 

 soon become alternate, and generally peltate; they are petiolate, 

 and covered with glandular hairs. 



(6). Cotyledons of medium size to small, reniform, entire; 

 primary leaves opposite, shortly petiolate, covered with glandular 

 hairs: mainly Stringybarks, with reniform anthers. — E. hevopinea^ 

 E. dextropiiiea, E. Wilkinsoniana, E. euyenioides, E. capitellata, 



