EUCALYPTUS TETRAGONA. 



Flinders's voyage ii. 599, t. 3), which to some extent holds the same position towards Eucalyptus 

 as Melaleuca towards Callistemon and as Tristania towards Metrosideros ; the coalescence of the 

 filaments of Melaleuca is one of degree only and even in the typical Melaleuca Leucadendron 

 afi^ects merely the very base of the staminal bundles. But as in all three hitherto known 

 Eudesmias hardly any concrescence of the filaments themselves is traceable, I deemed it best to 

 include them in the genus Eucalyptus, especially as calyx-teeth are still more strongly developed 

 in E. odontocarpa and E. tetrodonta. The denticulated calyx of these Bucalypts ofi'ers an approach 

 to the genus Angophora, which indeed can only be kept strictly separated by the development of 

 distinct petals, the operculum of Eucalyptus being truly calycine, unless a tender membraneous 

 free inner lid of rare occurrence should be regarded as a transit to some petaloid structure. The 

 genus Eucalyptus — well marked as it is — shows further some affinity to a genus of the Pacific 

 Islands, namely Acicalyptus (A. Gray in "Wilkes' United States Exploring Expedition 651, t. 67), 

 in which however the petals are developed, though sometimes irregularly so, and in which the. 

 fruit becomes succulent in its outer portion, maturing only one or two large seeds with thick 

 cotyledons, so far as this could hitherto be demonstrated from a congener restricted to Lord Howe's 

 Island (F. v. M., fragmenta phytographias Australiee viii. 16) ; the two-celled ovary, characteristic 

 for Acicalyptus, is also typical for Eucalyptus phcenicea and occurs though very exceptionally in 

 at least one other species (E. traohyphloia). The so-called Eucalyptus-forests of New Ireland, 

 mentioned by the Reverend George Brown, are possibly formed by a species of Acicalyptus. The 

 affinity of Calyptranthes, a genus widely spread over tropical and subtropical America, is more 

 remote, though its petals are generally only rudimentary, or as in Eucalyptus also quite absent. 



Explanation of Analytic Details. — 1, unexpanded flower, its lid lifted ; 2, longitudinal section of an 

 unexpanded flower ; 3, longitudinal section of an expanded flower ; 4, some stamens in situ ; 5 and 6, front- and 

 back-view of an anther, with a portion of its filament ; 7, style and stigma ; 8 and 9, longitudinal and transverse 

 section of fruit ; 10 and 11, fertile and sterile seeds ; all magnified, but to various extent. 



