142 MR. G. BKNTHAM OX MYRTACE^T:. 



jected to by F. Mueller, chiefly, I believe, on the ground of its perfect 

 continuity with the calyx-tube in the bud of many species with- 

 out any circular rim or apparent articulation ; that, however, may 

 be observed in the buds oi Angopliora^ as w^ell as of some species of 

 Darwinia and other Chamgelaucieae, w^here the minute calyx-teeth 

 leave a broad interval between them. The arguments adduced by 

 Brow^n (App. Flind. Voy. ii. GOO, Works, ed. Benn. i. 75) to show 

 that in Eitdes^nia at least the operculum is formed of confluent 

 petals only, and that in E, glohitliis^ and other species w^here it is 

 double, the outer one may be considered to be formed of the calyx 

 and the inner one of petals alone, have been further confirmed 

 by subsequent observations. The species, however, where the 

 outer operculum exists at an early stage have proved to be much 

 more numerous ; and in E, platypliylla and E. mactdata it is much 

 thicker and more persistent than usual, marked often with promi- 

 nent ribs corresponding with those of the calyx-tube. On the 

 other hand the species where, notwithstanding its apparent homo- 

 geneity, the operculum is probably composed of both floral enve- 

 lopes united, seem to me to be much fewer than was supposed by 

 Brown. The only one where there may be corroborative evidence 

 of the hypothesis is perhaps E. erythrocorys^ where the exceedingly 

 thick fleshy operculum is marked with four raised ribs correspond- 

 ing to those of the calyx-tube, and between them are ribs and 

 raised veins, which may be presumed to be those of the petals. 



It is remarkable that a genus so extremely abundant, both m 

 species and in individuals, throughout Australia, from the alpine 

 regions of Tasmania and Victoria to the arid burning deserts of 

 the northern coast, should scarcely have been detected beyond its 

 limits. JN"o Eucalyptus is known from New^ Zealand or from T^^"^ 

 Caledonia. Two only of the northern species have been also found 

 in Timor; but beyond that we have no satisfactory evidence of 

 any extension of the geographical range of the genus. Four 

 species, indeed, are given in books as natives of the more distant 

 islands of the Indian archipelago ; but it does not appear that any 

 native specimen undoubtedly referable to the genus exists in any 

 of our herbaria. Of the four species referred to, the one that 

 rests upon the best grounds is perhaps E. mohiccana, Koxb., 

 described in his * Flora Indica,' Ii. p. 498, from a tree in 

 Calcutta Garden, said to be a native of the Moluccas, but with- 

 out any record as to when or by whom introduced, and I can- 

 not find that any specimen or drawing has been preserved. Mi- 

 quel refers it to E. alba, Eeinw\, a native of North Australia and 



the 



