310 Mr. Griffjth on the Root-Parasites referred to Rhizanthese, 



not limited to one particular group of Monocotyledons, but is presented to 

 us at the three different points of Smilacinece and Dioscorece ; Taccece ; and 

 Aroidece. 



The occurrence among Dicotyledons of the characteristic number oi Mono- 

 cotyledons is much more diffused, for it is found in Anonacew, Berberidew, 

 Menispermece, &c. ; in Aurantiacece, Olacinece, Limnanthere, Meliacece, Ebena- 

 cece, Asarinece, Loranthaceoe, &c. 



It may also be urged, and especially with reference to the situation of Rhi- 

 zanthecB as a single group, that there is not, perhaps, a variation in form or 

 in structure of primary importance in Dicotyledons that may not be met with 

 in Monocotyledatis and Acotyledons, and vice versd. Thus the conical trunk of 

 Dicotyledons is imitated by Bambusa, and in a very marked degree by some 

 Dracoence*. The cylindrical trunk of Monocotyledons is imitated by Cycadece, 

 by Tree-Ferns, and these again are sometimes beautifully imitated by the 

 stem of Carica Papaya. The frondose form of growth of Hepaticce appears 

 in Podostemon. The dichotomy of Fuci is of common occurrence among 

 Naiades, and Fungi are curiously imitated l)y some of the plants grouped 

 among Rhizanths. And this interchange is in some form or other so gene- 

 ral, that it may perhaps be said, that the existence of a peculiar structure 

 in one subkingdom predicates its existence or its representation in the two 

 others. 



It therefore appears to me consistent with the order of nature, that the 

 analogue of the reproductive organ of Acotyledonous plants (at least of those 

 which appear to have sexes) will, whenever it be found f, be found both among 

 h 0*!} liOi^nt iti If «spfit) 



* I was first struck with the resemblance certain Dractena have to Dicotyledonous trees in the forest 

 of Pulo Bissar near Malacca, in which there is a large arborescent species not to be distinguislied from 

 an ordinary Dicotyledonous tree, except by inspection of the leaves. On arriving here, in the progress 

 of clearing, &c., so as to form a botanical garden, I examined casually several shrubby species of the 

 same genus, and was surprised to find that the resemblance was not confined either to the mode of 

 branching or the exterior of the trunk. The mixture of Endogenous and Exogenous characters is in- 

 deed remarkable ; and I am disposed to coincide with Mr. Grant, who has set up several specimens in 

 his usual beautiful style, that apparently, and very probably partially, the new formations of woody 

 tissue are added to the outside. The figure of the remarkable Exogenous stem in Lindley's ' Intro- 

 duction to Botany,' 2nd edition, f. 42. p. 100, resembles at first sight that of a Dractena. 



t I do not feel myself competent to enter on the question whether these homogeneous acotyledonous 

 forms of embryo do constitute the required representations of the spores of Acotyledones. The study of 

 their development and of their germination is an essential requisite in the settlement of this point. 



