106 New Genus of Plants ^ named Macraa. 



of the calyx has three costae, one occupying the axis, and one 

 running along each margin, and becoming conlluent beneath 

 the sinuses. In Frankenia, therefore, the costa; of the calyx 

 occupy the place of the intervenia of Macraea. 



Having thus instituted comparisons with those orders, to 

 which Macraea bears the greatest apparent resemblance, I 

 must next proceed to advert to another natural assemblage, to 

 which it offers, indeed, no prima facie characters of affinity, but 

 near which it is, nevertheless, probable that it will ultimately be 

 arranged ; the order to which I now allude, is Geraniaceae. It 

 is true, that the elastic coccus, the lobed leaves, the succulent 

 habit, and thickened joints, of Geraniaceae, are all absent in 

 Macraea, as well as a number of subordinate points of structure; 

 but there are others in which they remarkably agree. If we 

 understand the axis of the capsule of Macraea to be an elon- 

 gated torus analogous to that of Geraniaceae, and such an 

 opinion may be entertained with little difficulty, we have then 

 a fruit of a sufficiently similar structure to be compared to that 

 of Geraniaceae, Rutaceae, and other neighbouring tribes. In the 

 venation of the calyx there is also so material a similarity, that 

 if the distinct sepals of Geraniaceae were to cohere for half their 

 length, thus losing their membranous margin, we should have 

 a calyx little different from that of Macraea. The petals of both 

 have the same aestivation, are equally unguiculate, and their 

 principal veins, in hke manner, bend inwards, and become 

 confluent with each other within the margin. The stigmas also 

 are several, and the insertion of antherae is not materially 

 different. 



For these reasons it may be concluded, in the absence of 

 more complete evidence, that the affinity of Macraea is far from 

 close with any of the known orders of plants ; that it probably 

 occupies an intermediate place between those whose fruit is 

 destitute of axis, as Frankeniaceae and others, and those vvhose 

 fruit consists of carpella, adhering to an elongated axile torus, 

 as Rutacae, Geraniaceae, &c., and that its greatest apparent re- 

 lation is with these last. 



