

L A C A C E M. 301 



The aestivation of the corolla at once distinguishes it from all other 

 Icacineous genera, except the Biirsinopetalum of Wight, which also 

 has an imbricative aestivation, according to Mr. Miers. On which 

 account, indeed, this acute author, in his profound and elaborate 

 memoirs on the Olacinece, Icacinece, &c.,* refers both Biirsinopetalum 

 and Blume's Pleuropetalon (which he supposes to be one and the same 

 genus) to the order Aquifoliacece, next to the anomalous genus Villa- 

 resia. But, from the examination of one or two young flower-buds of 

 Biirsinopetalum arboreum, I should say, with Dr. Wight, that the 

 aestivation of the thick petals was of the valvate kind, as truly so as 

 in Clematis. Their thick and abrupt edges appear to be apposite 

 throughout, next the base without any modification, while higher up 

 a thin margin is induplicate, and at the apex these thin margins, 

 more strongly induplicate, form the deeply inflexed apical appendage. 

 In Pleuropetalon, at least in our species (for I have not seen that of 

 Blume), the imbricative and the induplicate- valvular modes of aesti- 

 vation are truly combined in the same organ ; the thin edges of the 

 petals overlapping each other, in the normal quincuncial manner, 

 except near the apex, where the inflexion begins : here their margins 

 abruptly become induplicate, as is represented in the accompanying 

 figures, bringing this portion of the aestivation into the valvular cate- 

 gory. The aestivation of the corolla seldom affords an ordinal cha- 

 racter free from all exceptions ; and the modification in these two 

 genera would seem wholly insufficient to exclude them from the Ola- 

 cacece, or Icacinacece, unless supported by other characters; whereas, 

 in fact, they appear fully to accord in all other respects with the 

 characters assigned by Mr. Miers to his Icacinacece. Pleuropetalon at 

 least, with its simple pistil, one-celled and biovulate ovary, and 

 slender style, would surely seem much out of place in Aquifoliacem. 

 As to the generic difference between Bursinopetalum and Pleuro- 

 petalon, now confirmed by a second species, apparently there can be 

 little question. Biirsinopetalum has a merely five-lobed calyx, with 

 its tube adnate to the ovary, which contains a single ovule, and is 

 surmounted by a very short and conical style. Pleuropetalon has a 

 calyx of five distinct sepals, entirely free from the biovulate ovary, 

 and the style is long and filiform. Its fruit unfortunately is unknown. 



* In the Annals and Magazine of Natural History, New Series, vols. 8, 9, 10 ; 

 especially vol. 8, p. 169, and 9, p. 223. 



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