10 



ENDOGENS. 



the adhesion of the stamens to the style in Orchidece has its parallel in Stylidiacece, all which coincidences may tend to bear out the idea that the Endogens and Epigynous Exogens are branches 

 of nearly allied subdivisions of the cryptogamous families. (V. Tab. II.) 



With regard to the division of the Class Endogens, proposed in Trans. Linn. Soc. Vol. XXII. p. 409, further observations have given me an increased confidence in its practicability, as there 

 does not appear to be any close connection between the Endorhizal and Exorhizal families as now separated, except that of Juncacem and their allies on the one hand, with Liliacece and their allies 

 on the other, and these may by further analysis prove to be sufficiently distinct. The position of Palmacece, and also of Taccacece, then appeared to me to be doubtful, but the subjoined notes will 

 I hope leave their affinities no longer a question. 



With the Endorhizal families, however, are included several in which the germination as far as the primary radicle is concerned is exorhizal, as I then particularly noticed ; but as the 

 endorhizal character is probably one of much importance, it should occupy a prominent position notwithstanding the exceptions.* It deserves notice also, that with the Endorhizal families 

 are naturally included all those in which the bulk of the embryo consists of an enlarged radicle, as unnatural combinations must follow their separation. The Endorhizal Section is therefore to be 

 understood as having reference only to alliances, those alliances containing families the germination of which is endorhizal, or the embryo macropodal being placed together under this head. 

 Should, however, these characters prove insufficient for the purpose of effecting a division of the Endogens, yet I believe they may be naturally arranged in two Races, springing respectively from 

 Zosteracecv and their allies and Aracece and their allies, the former of which may be termed as now Endorhizal, on account of its. containing all the families known as being Endorhizal, or as at all 

 likely to prove to be so. 



Desvauxiace^e. 



This family presents the remarkable character of having the single carpel always posterior, the only instance I have met with in the Endogens. It may be regarded as decidedly 

 indicating the lowest developed, or at least the most retrogade form of the Endorhizal Section. The single stamen is also posterior, a very rare character, as in all other instances (except in 

 Callitriche) in which it has appeared to be posterior, it alternates with the posterior petal, and is therefore not directly posterior. 



TACCACEiE. 



I have now no doubt that this family is nearly allied to the Orchidea, having very recently had an opportunity of observing that Tacca has precisely the embryo of Burmanniacea, it being 

 attached by a suspensor like a thread-like funiculus to the thin layer of albumen which intervenes between the cavity in which it lies and the hilum (fig. 1). It therefore agrees with the embryo of 

 Dictyostega, as described by Mr. Miers,f and with that of Thismia, although the suspensor in the latter instance is often indistinct. In Tacca the funiculus is firm, it being difficult to detach it 

 without injury to the embryo itself. The embryo is a simple ovoid body without any trace of a plumule. These well-marked characters appear to me to remove Taccacea* far from Aracece, to 

 which they have been compared, and to associate them exclusively with Orchidece and their allies. 



t I. e. supposing the origin and place of attachment of the funiculus in the latter genus to be the same, and it is not at all likely to differ. 



