31 



Table V. 



The Casuarinal, or Amentaceous Division. 



That the families here associated are a branch of the Gymnosperms, I believe there is no reason to doubt, Casuarina having been compared to Ephedra by Dr. Lindley, but as Chloranthacea 

 are decidedly in nearer affinity with Gnetacem than Casuarina, I prefer regarding this Division as branching from the Coniferce and place Gnetacece in Table III. See also p. 6 & 7. 



There is however a yet nearer approach taking place between Taxacece and Myricacece, as they do not materially differ either in habit or inflorescence, and perhaps another decided evidence 

 of affinity may exist between Taxacece and this Division in the foliaceous branches of Xylophylla*, which are almost identical with those of Phyllocladus ; and, if foliaceous branches may be compared 

 with leaves, which is perhaps admissible, some Euphorbiaceous plants at first sight very much resemble Cycadece, showing a further analogy with the Gymnosperms. And it may also deserve notice 

 that a species of Podocar pus, the Myrica Nagi of Thunberg, has, under the name of Nageia, a supposed distinct genus consisting only of that species, been referred successively to Myricacece, 

 Taxacece, and Euphorbiacece. 



Subdivisions are here scarcely practicable, but the two forms, Urtical and Casuarinal, are so far distinct among the Apetalous families as to deserve notice. 



The genus Wormskioldia appears to me to be very near Turnera, differing perhaps more in the form of the fruit than in any other character ; the reticulated seeds, with the almost peculiar 

 aril, so closely resemble those of Turnera, that I doubt if they could in some instances be readily distinguished, and there is a tendency in the foliage of Turnera, where the leaves are narrow and 

 bluntly serrated, to assume the Cruciferous habit of Wormskioldia. 



ApOCYNACEiE. 



This family, from the agreement of its structure with the Asclepiadecz, may be compared in almost the same manner as that family with Violacea, with which they agree in their crested 

 anthers; and to Euphorbiacece they perhaps have some affinity, as Rauwoljia agrees with them in habit, and they have nearly the same acrid and poisonous qualities, Vahea madagascariensis agreeing 

 with them also in the production of caoutchouc. Where the ovules are two and suspended, I have seen the same peculiar twist in the raphe which occurs in Scolopia among Flaeourtiacece, and the 

 anther of this genus has a remarkably elongated crest. By placing them here they are in Table VII. brought into their natural position close to the Loganiacem. 



Euphorbiacece. 



The affinities of this family are more than usually complicated, but as it is generally admitted that they are very near StilaginecB, Scepacece, Urticacece, and their allies ; their remaining 

 affinities, which are widely different, may be regarded as scarcely more than analogies. Of these the approach between them and the Malvacece and Byttneriacece is the nearest, but, besides other 

 differences, the involucre of Euphorbiacece is like those of Morece and Urticacece, consisting of the leaves of the stem reduced in size, whereas in Malvacece it is like such an involucre as that of 

 Hernandia, consisting only of bracts on the pedicels at the base of the flower, and consequently rarely contains more than one flower. To Stilaginece and Scepacece they approach so nearly, that 

 they are more distinguished by their habit than by any positive difference in structure, and it does not appear certain that the limits between them and Stilaginece are as yet clearly defined. As a 



* The apparent leaves of the genus Xylophylla are true branches, because in one of the species all the branches are in the first stages of their growth foliaceous like the apparent leaves of other species, but they subsequently contract so as to 

 form the permanent rounded woody stems. 



