172 flora indica. [Mevispermace/v 



woods, but there are few natural orders of any extent amongst whieh scandent genera 

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

 scandent 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 scandent ones, and even in some cases imitates the latter, and the value of 

 the fact in its broadest aspect is considerably diminished, 



Menispermacece 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 pleurenchyma, 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 Memspermacece, as Kad- 

 suracece, Anonacece, and Clematidea, and also to plants having no direct affinity with 



these or with one another, as Phytocrenece, Nepenthece, Chloranthacea, Malpighiacea* 

 some Siditalacea, Balanoyhorece , Piper acece, Comb ret ace a, Verbenacece, Vitis, etc., 

 and some scandent LeguminostP and Composite. 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 Menisperrns suggests three subjects of in- 

 quiry:— 1. Do they indicate a high or low position of Menispermacece \ amongst 

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

 affinity 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 Ranunculacece, will be 

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

 Menispermacece y 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 

 Cosci >im 9 than in Magnolia, or most other Exogens of the same age ; for whereas 

 there is in most ordinary Exogens an annual rej>etition of parenchyma and pleuren- 

 chyma, with few large vessels, but without change in relative position, and with little 

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

 Menispermacece 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 buudles 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 Menispermacece is alway 

 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 arrangement 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 w r e may not be able to recognize the func- 

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

 fully developed, it implies the existence of a function in either a latent or active 



condition. 



Decaisne, in his admirable essay on Lardizabalece, has thrown great light upon 

 the structure of Menispermeous wood, and treated the whole subject, in its many 

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

 between the age^. of the particular organs and some of the abnormal characters 



