39 



Table VIL 



SHOWING THE LATERAL RELATIONS OF THE DIVISIONS OF THE EXOGENS. 



The intention of this Table is to bring the entire of the families of the Exogens, into their mutual relations with each other, so as to show at one view, both their vertical and lateral relations, 

 and completely so, their lateral relations being but partially indicated, as the Divisions stand separately in the Tables, I believe this to be the only mode of arrangement which can possibly be made 

 to accord with the well-known maxim of Ray, " Methodum intelligo naturce convenientem qua nec alienas species conjungit, nec cognatas separat," (families in the present comparison being 

 understood instead of species), and it so far fulfils it, as to show that the Divisions in the foregoing Tables must be at least to some extent natural. 



I believe Ray's idea to be strictly correct, and that it might be extended not only to families but to Divisions, and that its truth might be clearly demonstrated in such a Table as this, by 

 using curved instead of straight lines, so that the forms of the Divisions might be varied to suit affinities. The relative spaces the Divisions occupy might also be varied, and promontories might be 

 made as in maps, but this being the first attempt of the kind, (except the sketch in the Ann. Nat. Hist. 2nd Ser. vol. XL, Tab. III.,) I thought it would be better not to complicate the arrangement 

 more than was absolutely necessary to show the relative positions of some of the most extensive and remarkable families. 



This I believe is for the most part effected, even in the Polypetalous families where affinities are the most complicated; as for instance, Combretacece find their place very near Myrtacea, 

 Vacciniacea near Cinchonacea, and Passifloracece near Homaliacea ; among the perigynous and hypogynous families, Euphorbiacea fall very naturally into their nearest affinities being in 

 immediate contact with Menispermacea and Rhamnacea, and are contiguous to the Division containing Malvacea; and Ochnacea are contiguous to Violacea, so that whether the former are placed 

 in Table IV. or in Table V. their station in Table VII. would not be materially altered. Saxifragacea and Rosacea are however widely separated, and also Olacacea and Icacinacea 9 but I believe 

 there is no certain evidence to show that these families are nearly related, and their approaches although so near may be only those of analogy ; but these are questions requiring further attention 

 whatever the decision may be.* Among the Apetalous and Monopetalous families equally natural approaches between the families are evident, and I think it deserves notice that all the didynamous 

 families with the labiate corolla are brought into close contact with each other, because at first sight it might appear that in Tables III. and VI. they are widely separated. 



Till these Divisions however have been thoroughly examined, and admitted by competent botanists to be well established, it would be premature to carry out this plan of showing what may 

 be termed lateral affinity, any further ; but I think it will be obvious that a Table of this kind is really a sine qua non as regards the accomplishment of the Natural System of Exogens. 



If it were wished to place Table VI. in relation with Table IL, so as to bring Icacinacea md Phytocrenea into relation with Olacacea, and what would perhaps be equally natural Rosacea into 

 relation with Saxifragacea, it might be effected without any further alteration than by placing Table VI. between Tables II. & IV., leaving Homaliacea in relation with Passifloracea. This 

 would require Table VI. to be regarded as a branch of Table IL, and it could not then be considered as having any relation to the Gymnosperms, but it appears to me that Platanacea are much 

 too near Cupulifera and Artocarpece to allow such an alteration. Possibly from the position of the radicle in Platanacea and Proteacea, Table V. should be placed before Table VI., or what would 

 be preferable, placed with it in the most advanced position. 



* V. p. 13; Phytocreneae p. 35, and Icacinaceae p. 36. 



