173 FLORA INDICA. [MeruKjH'rmacets. 



woods, but there are few natural orders of any extent amongst which scandeut genera 

 are not to be found ; these have often no further relation to one another than their 

 scandeut habit, and the woods of nearly-allied species often differ essentially ; add to 

 these, the fact that the wood of erect Exogens sometimes presents as great anomalies 

 as that of scandeut ones, and even in some cases imitates the latter, and the value of 

 the fact in its broadest aspect is considerably diminished. 



Menisjiermacea exhibit very unequally, but always more or less, certain features 

 common to most scandent plants ; as, a spongy stem, abundance of cellular tissue, 

 and of sclerogen cells in it, laxity of plenrenchyma, irregular development of woody 

 bundles and liber, absence of rings of annual increase, wood often wholly composed 

 of dotted, scalariform, or pitted vessels, always accompanied by many of very large 

 diameter, and lastly, great anomalies in the structure of the pith. 



Such characters are more or less common to the allies of MejiispermacetB, as Kad- 

 suraceiB, Anonacece^ and Clematideis, and also to plants having no direct af&nity with 

 these or with one another, as Phytocrenem, Nepenthea, Chloranthacea, Malfighiacea, 

 some Sa?italaceiSy BaJanophoreee, FipemceiSt Combretacece, Verhenacem, Viiis, etc., 

 and some scandent Lei/unmwsip and Cowposita. Amongst all these the only re- 

 cognizable relation between function and structure is, perhaps, the fact that the lax 

 tissues and abundance of large air-vessels in the wood, ensure a free circulation of 

 fluids and gases through vessels which, by reason of the many convolutions and 

 contortions to which they are subjected, are peculiarly exposed to constriction. 



The prevalence of these peculiarities in Menisperms suggests three subjects of in- 

 quiry: — 1. Do they indicate a high or low position of Menisperma^ecSt amongst 

 Exogeus? 2. Do they indicate a transition to Endogens? 3. Do they betray any 

 afSnity with other natural orders placed at a distance in our systems ? 



1. At the outset of the first of these questions, we are met by the inquiry, what 

 constitutes perfection and imperfection in wood structure, and indeed in the Vegetable 

 Kingdom generally ? Under the notes that are appended to Manunculacene, will be 

 found some on comparative complexity in the floral organs, which are applicable to 

 Menispermacece, and which argue their belonging to a low type. But, by a parity of 

 reasoning, the same arguments applied to the wood of this Order may by some be as- 

 sumed to indicate a highly developed type. In illustration of this, we may remark that 

 there is much more complexity in the construction of a three years old stem of 

 Ciisi-iintmi, than in Magnolia, or most other Exogens of the same age; for whereas 

 there is in most ordinary Exogens an annual repetition of parenchyma and pleuren- 

 chynia, with few large vessels, but without change ia relative position, and with little 

 variation in the structure of the component parts of each year's growth, we have in ■ 

 Mi'inspt'nnace^e many structurally different forms of cellular and vascular tissue an- 

 nually developed in the stem, besides liber-bundles, and further, in some, a double 

 system of Exogenous bundles of wood and of liber is developed, wholly indepen- 

 dently of those first deposited. 



It may be argued, that the great prevalence of parenchyma, and constant irregula- 

 rities in the development of the various vascular tissues, denote imperfection; when 

 it will be answered, that during several years the growth of Menispermaccie is always 

 normally Exogenous, that the simplest theoretical plan upon which this could be con- 

 tinued would be by the annual repetition of the same, and that a deviation from this 

 type and ari-angement implies a modification of structure for another and higher 

 function ; in short, that, in the vegetable as in the animal kingdom, specialization 

 and complexity of organs for the performance of special functions implies relative 

 elevation in the scale. It is true that we may not be able to recognize the fuuc- 

 lion, but in this, as in all similar cases, we must assume that when a structure is 

 I'uUy developed, it implies the existence of a function in cither a latent or active 

 condition. 



Decaisne, in his admirable essay on Lardi:aiah',e, has thrown great light upon 

 the structui-e of Meuispermeous wood, and treated the whole subject, in its many 

 bearings, in a must masterly manner ; he indeed was the first to show the relations 

 between the ages of the particular organs and some of the abnormal characters 



