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ON THE CHARACTERS AND AFFINITIES OF THE GENUS COLON, 



By David Don, Esq. Libr, L. S. Communicated by the 

 Author, 



The present genus is one of those whose characters are con- 

 <;ealed under a peculiar habit, which renders it often difficult, if 

 not impossible, to determine with certainty their natural affi- 

 nities. I was at first inclined to consider Codon as belong- 

 ing to the Solanece, and indeed the curved embryo, and the 

 striking resemblance in habit, appeared strongly to favour 

 that arrangement ; but a more intimate examination has shewn 

 these views to be untenable, and that its affinities must be 

 looked for among other families. In Codon the flowers are 

 symmetrical, the stamens epipetalous, the anthers incumbent, 

 with parallel cells, the style duplicate, and the capsule com- 

 posed of two valves, with the septum formed by the ap- 

 proximation of the two prominent placentae, the ovula erect, 

 and the seeds albuminous, with the embryo about equal its 

 length. On comparing these characters with those of the Hy^ 

 droleacece, we shall find that they accord in a very remarkable 

 degree ; and although in Codon the stamens and divisions of the 

 calyx and corolla are doubled in number, the symmetry of the 

 flower is preserved, and the mere increase of those parts are of 

 comparatively little importance, when the number of points of 

 agreement are taken into account. In Codon, and in some of 

 the Hydroleaccw, particularly in Wigandia, the leaves have a 

 lobed margin, and are clothed with bristly points, which, in the 

 former genus, are developed into prickles. The stamina and 

 pistilla entirely coincide in both genera, but the albumen is more 

 copious, and the stigmata less developed in Codon, whose affi- 

 nity, however, to the Hydroleacece, may be considered as com- 

 pletely established. Cordia decandra may be instanced as an 

 example of increase in the number of stamina in a family very, 

 nearly related to Hydroleacece, The Cordiaceoe appear to con- 

 stitute a group intermediate between that family, Convolvulacea^ 

 and BaraginecB ; and, by means of the smal^ group of HydrO' 

 phyllecB, which is distinguished by a completely unilocular ova- 

 rium, and by a minute embryo placed at the extremity of a 



