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 OF CENTRAL AFRICA. 283

the order Rcscdaccnc is not included in the first or second part of his 'Prodomus/ and I can find no observation respecting it in these two vohnnes. It is probable, there- fore, that he may intend to i)lace it near Passiflorcoc, as sug- gested by M. Tristan, or, which is more likely, that he has adopted the hypothesis lately advanced, and ingeniously snpported, by Mr. Lindley, respecting its structure and affinities.-^

According to this hypothesis, in Reseda the calyx of authors is an involucrum, its petals neutral floAvers, and [220 the disk or nectary becomes the calyx of a fertile floret in the centre; and, as a deduction from this view^ of its structure, the genus has been placed near Euphorbiacca?.

The points in the structure of llescda, which appear to have led Mr. Lindley to this hypothesis, arc the presence and appearance of the hypogynous disk, the anomalous structure of the petals, and the singular aestivation of the flower; but it is no shght confirmation of the correctness of M. De Jnssien's opinion, that all these anomalies occur in a greater or less degree in Capparidea), and have been found united in no other family of plants. The remarkable a3sti- vation of Reseda equally exists in Crateva, and in more than one subdivision of the genus Cleome; the hypogynous disk is developed in as great a degree in several Capparidea); and an approximation to the same kind of irregularity in the petals occurs in two sections of Cleome.

The analogical argument alone then might, perhaps, be regarded as conclusive against the hypothesis. ]]ut the question, as far as relates to the petals, and consequently to the supposed composition of the flower, may be decided still more satisfactorily on other grounds. Both MM. Tristan and Lindley regard the upper divided membrana- ceous part of the petal as an appendage to the lower, which is generally fleshy. On the other hand, I consider the anomaly to consist in the thickening, dilatation, and inner process of the lower portion, and that all these deviations from ordinary structure are changes which take place after

' Callecf. But. tab. 22.

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