176 Mr. J. Miers on the Affinities of the Olacacea?. 



tion of the nature of the cupuliform disk. There is however 

 always this essential difference constantly existing between the 

 two families : in the Olacacece the insertion of the corolla and 

 stamens is on the margin of the disk ; in the Santalacem this in- 

 sertion is always outside of it ; in the former these organs are 

 articulated with it, and easily fall away ; in the latter family it is 

 impossible to separate the free lobes of the perigonium and sta- 

 mens without force, and a rupture of the parts. But notwith- 

 standing these prominent marks of ordinal distinction, there 

 exists a regular gradation from one family to the other, as will 

 be seen from the analyses I propose to offer ; this proceeds from 

 one extreme, Opilia (where the disk is developed in distinct free 

 glands), through Agonandra, Olax, Liriosma, Cathedra, Schbpfia, 

 Arjoona, Quinchamalium, Myoschilos, Iodina, Cervantesia, Mida, 

 Exocarpus, Santalum, &c, rendering it difficult, through the 

 osculant genera Iodina and Cervantesia, to draw a line through 

 the strong limits of demarcation that exist between the two 

 families. 



The word torus has been employed by Mr. Bentham (Linn. 

 Trans, xviii. p. 676) to describe in Olacacece what I have termed 

 a disk, and which I have shown to be the same organ, but dif- 

 ferently situated, that forms a constant feature, both in that 

 order and the Santalacece, where in both cases, with rare excep- 

 tions, it is always deeply cupuliform and more or less lobed on 

 its margin. I have adopted in preference the term " discus cu- 

 puliformis " as that given by Dr. Lindley for such a structure 

 in his ' Introduction to Botany/ p. 161. This may not differ in 

 its nature from a stipitate torus, but the adaptation in such cases 

 of this last term, which is generally used in another sense, will 

 naturally lead to ambiguity in our definition of structural ar- 

 rangement ; thus Mr. Bentham, in a subsequent work, appears 

 to agree with Dr. Hooker's observation, after an original sug- 

 gestion of Mr. Brown, in what appears to me an inconsequent 

 conclusion, viz. that because in Olacacece the corolla is inserted 

 into the disk, which is sometimes stipitate, or what he calls the 

 apex of the pedicel, that the calyx in such case should be consi- 

 dered in the light of an involucre (Flor. Nigrit. p. 261). I can 

 perceive no reason why this should be a necessary consequence, 

 for we see in the Capparidacece the development of the stipitate 

 torus carried even to a much greater extent, supporting the sta- 

 mens on its sides and the petals below them ; but no botanist in 

 these instances has ever thought of considering the calyx to be 

 of the nature of an involucre, which it ought to be if the above 

 reasoning were valid : this incongruity is rendered still more evi- 

 dent, when we remember that the argument was applied in the 

 case of Rhaphiolepis, a genus of the Icacinece, which I have shown 



