RAPFLESIA ARNOLDI. 413 



[332 



horecB 



I may hereafter have an opportunity of entering fully 

 into the question whether Kctfflesiaceoi and BalanopJw. 



received several names, as vasa povosa, punctata, vasiform cellular tissue, 

 dotted ducts, &c., and which are so conspicuous in the majority of arborescent 

 Phaenogamous plants, have never been observed in any part strictly belonging 

 to these parasites. But even admitting tlie non-existence of the large vessels 

 here referred to, their absence will hardly be regarded as a sufficient reason for 

 the union into one class of the two families in question, especially when it is 

 considered — 



First. That conformity in vascular structure, even when accompanied by 

 peculiarity of tissue, does not always indicate, much less determine, botanical 

 affinity. This is strikingly exemplified in ConifercB and Winlermiece, two 

 families which, though so nearly agreeing in the uniformity and peculiarity of 

 tlieir vessels, and in both of which the large tubes referred to are wanting, yet 

 differ so widely from each other in their organs of reproduction and in their 

 leaves, that they may be regarded as placed at opposite extremities of the scale 

 of Bicotyledonea. 



Secondly. That uniformity of vascular structure is not always found in 

 strictly natural families. Thus many tropical woody climbers exhibit remark- 

 able peculiarities of vascular arrangement not existing in the greater part of 

 the families to which they respectively belong, but whioli peculiarities appear 

 to have no influence wiiatever in modifying their reproductive organs. 



Thus also in Myzodend,roit> the whole woody tissue consists of vasa scalari- 

 formia, a |)eculiar structure, and very different from that of all the other genera 

 belono'ing to Loranthacea, to which this genus has been referred, and to which, 

 though it does not absolutely belong, it is nearly related. Even this pecuhar 

 structure of the stems of Myzodendron admits of considerable modifications in 

 the different species of the genus, which is strikingly exemplified in comparing 

 the loose vascular tissue with large and singularly constructed medullary rays 

 of M. braeliystachyum and quadriflorum with the more minute vessels and ex- 

 tremely narrow rays of M. punclulatnm. 



I may also notice that in Tillandsia mneoides, as well as in the nearly related 

 species of that genus, the capillary stems are destitute even of spiral vessels, 

 though in Bromeliacea generally the ordinary vascular system is found. 



Whatever may be the state of vessels in the fully developed parasites belong- 

 ing to RafflesiacecB, it appears to me that at least Rafflesia in its very early 



1 Myzodendron of Banks and Solander, from /ttujsw or {jtvla sugo, and ^kvl^ov, 

 has been changed to Misodendron by De CandoUe and all following systematic- 

 v/riters; no doubt merely from a mistake as to the intended derivation. Myzo- 

 dendron, liitherto referred to Lo-mnthacea, to which it is certainly closely allied, 

 especially through Jnlidaphne of Poeppig, appears to me to have cliaracters 

 sufficient to distinguish it as, at least, a suborder or tribe {Myzodendrea), 

 namely, the structure of its ovarium, in which it approaches to Santalacea;, 

 havin" three ovula suspended from the apex of a central placenta, only one of 

 which" ripens ; the entire absence of floral envelope in the male; the singular 

 feathery appendages of the female flower and fruit compensating in the dis- 

 persion and subsequent adhesion of its seeds, which are destitute of tliat 

 viscidity existing in those of the parasitic Loranthaceie ; and lastly, the embryo 

 being undivided, with its dilated and exserted radicle enclosed in a semi- 

 transparent covering, a continuation of the membrane lining the cavity of tlie 

 albumen in which the embryo is lodged. 



