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XXII. On Acradenia, a new Genus o/'Diosmese. By Richard Kippist, Esq., Libr. L.S. 



Read June 1, 1852. 



1 HE plant to which I propose to call the attention of the Society this evening, is one of 

 a highly interesting collection, formed in the neighbourhood of Macquarie Harbour, by 

 the indefatigable Secretary of the Royal Society of Van Diemen's Land, Mr. Joseph Mil- 

 ligan, by whom, through the instrumentality of our lamented member, Mr. Bicheno, they 

 were kindly presented to the Society. 



It belongs to the Diosmeous section of Butacece (Tribe Boroniece), and m habit most 

 nearly approaches Zieria, to the larger-leaved species of which it bears, at first sight, con- 

 siderable resemblance. From this genus, however, as well as from Melicope, Boronia, 

 and Cyanothamnus, it is readily distinguished by the quinary division of the parts of the 

 flower, and by its more numerous stamens. Prom Erlostemon, Crowea, and Philotheca, 

 with which it agrees in the number of its floral organs, it differs in having perfectly 

 glabrous filaments, and smooth inappendiculate anthers ; and from the latter genus, 

 in addition, by the filaments being distinct, not, as in Philotheca, united below into 

 a tube. 



Another genus of Australian Biosmece with which it accords very nearly in many of its 

 artificial characters, is Geleznovia, a remarkable plant with the general aspect of Erio- 

 stemon, recently described by Turczaninow, from Drummond's Swan River Collections, in 

 the Bulletin of the Imperial Society of Naturalists at Moscow. The points of agreement 

 are, the quinary division of the calyx and corolla, the smooth subulate stamens (ten in 

 number), and glabrous inappendiculate anthers ; but the calyx in Geleznovia is coloured, 

 and as long, or rather longer, than the corolla, the anthers are strictly terminal, and the 

 entire surface of the carpels is covered with elevated tubercles, each surmounted by a tuft 

 of radiating hairs. 



From all the above-mentioned genera the Tasmanian plant is distinguished by the 

 structure of its ovaries, which adhere closely together, and are everywhere clothed with a 

 dense tomentose covering ; except that each bears, at its upper external angle, a naked 

 sessile tubercle or gland, large enough to be readily observed with the naked eye ; a cha- 

 racter which I have been unable to discover in any closely allied genus, and it has con- 

 sequently suggested the name Acradenia, by which I would propose to designate my 

 plant. 



I am unable to speak positively as to the precise nature of these glandular bodies, or 

 to say whether any exudation proceeds from them : when examined under the micro- 

 scope, they appear to be perforated by a tube, widening below, and communicating with 

 the internal cavity of the carpel. From the exact correspondence in their position, how- 

 ever, they are probably analogous to the cornute appendages which crown the ovaries of 



