212 DICTYOGENS. [Dictyogens. 



in Strelitzia, or even in the arborescent Aloes, and when it does become 

 evident it is unaccompanied by any peculiarity of the foliage. But, in the 

 perennial stem of Dictyogens the bundles are what this Anatomist calls 

 unlimited, that is to say, they go on growing for years together as in 

 Exogens. 



The principal difficulty about admitting the class of Dictyogens seems to 

 me to consist in the small number of genera and species which it compre- 

 hends, and in the absence of any evidence as to the stem of the order called 

 Parids having the anatomical structure here assigned to it. These objec- 

 tions are undoubtedly deserving of serious consideration ; but on the other 

 hand it must be borne in mind that the plants collected under Dictyogens 

 agree well with each other, and ill with any alliances of Endogens. 



The Natural Orders of Dictyogens are poor in species, and can hardly 

 be considered as established on recognised characters. The following; are 

 the distinctions, as far as they can be at present pointed out. 



Natural Orders of Dictyogens. 



Flowers 6 9. Perianth adherent. Carpels consolidated, several- 1 «„-,-. 



seeded . . J 68. Dioscoheacm. 



Flowers $9. Carpels several, quite consolidated. Placenta axile.\ ~ n c 



Flowers hexapetaloideous JbJ. Sjmilacejd. 



Flowers (3 . Carpels several, quite consolidated. Placenta park- 1 -„ -r, 

 ted. Flowers 3-6-petaloideom . ) ' °- Philesiace*. 



Flowers 0. Carpels several, half consolidated. Placenta axile.\ ~, w 



Flowers 3-petaloideous J71. Irilliace*:. 



Flowers 0. Carpels solitary, simple, many-seeded, with long-\ 79 p 

 stalked anatropal seeds and a basal placenta |/^. Koxburghiace^. 



In the Flora Antarctica, vol. II., p. 355, the foregoing views are ably combatted by 

 Dr. Hooker, who is unwilling to admit the propriety of recognising this class. He 

 considers that Callixene and Dryniophila, here placed among Liliads, undoubtedly 

 connect those Endogens with Sarsaparillas through Lapageria and Philesia. I do not, 

 however, feel disposed to abandon the opinions here expressed ; although it is very 

 possible that some genera now stationed among Endogens may require removal hither, 

 and others placed here to be excluded. If there is always a woody zone in the stem 

 of Callixenc, as Dr. Hooker found, then it may be more proper to consider whether 

 that genus is not a Smilaceous Dictyogon, than to reject the class of Dictyogens itself. 

 Dr. Hooker found the stem of Philesia essentially such as is here described, (his 

 description and mine differ more in appearance than in reality,) and that of Lapageria 

 rosea composed almost wholly of woody matter concentrated externally into a well- 

 defined zone. For my own part I am so little inclined to abandon the opinions here 

 expressed, that it seems more probable that the class ought actually to be strengthened 

 by the admission of Aristolochiads. 



