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A Monograph of the Family of Plants called Cunoniace*. 

 By Mr David Don, Librarian to the Linnean Society ; 

 Member of the Imperial Academy NaturjE Curiof?orum; of 

 the Royal Botanical Society of Ratisbon ; and of the Wer- 

 nerian Society of Edinburgh, &c. 



T.HE Cunoniacete were first proposed as a separate family 

 by Mr Brown from the Sa.rifrag'ea, to which they had been 

 referred by Jussieu, and to which they are' intimately related, 

 being chiefly distinguished by habit alone. M. Kunth consi- 

 ders them merely as a section of the SaxifraffCee, but it appears 

 to me preferable to regard them as a separate family ; for the 

 advantages arising from dividing extensive families and genera, 

 are, that the individuals composing them become better under- 

 stood, and their characters more accurately investigated. In 

 Willdenow's Species Plantaruin, there are only two species of 

 true Weinmannia; while in the present monograph they amount 

 to nearly thirty. The Sax'ifragecc are almost exclusively con- 

 fined to the northern, as the CunoniacecB are to the southern 

 hemisphere. Some pass beyond these limits, but their number 

 is very small. Both families agree In having entire and divided 

 petals, and a superior and inferior ovarium. I have occasion- 

 ally met with instances in Saa'iJ'raga clecipiens of trifid petals. 

 In the series of natural affinities, the Philadcljjhea clearly follow 

 the Cunoniacece, with which they correspond in liabit ; and in 

 Bauera and Polystcmon the stamens are indefinite ; and the seeds 

 of Caldcluvia have a striking analogy to those of Philadelphus. 

 The styles, both in SaxifrageeE and Cunoniacece, are often three ; 

 and in Cornidia of the Flora Peruviana, a genus closoly related 

 to Hydrangea, that number is always constant. The leaves of 

 Bauera, Mr Salisbury, who established the genus, and referred 

 it to the SaxifragecB, regarded as ternate, with an abbreviated 

 axis ; but they appear to me to be more properly simple, and 

 that the two lateral leaves are really modified stipules, — an opi- 

 nion which is confirmed by the presence in Caldcluvia of a pair 

 of stipules to each leaf; and, were they more developed, we should 

 have precisely the same structure as in Bauera. M. Kunth, who 



