3S9 
Class IV. IIHIZANTHS. 
j Rhizanthe^e, Blum. FI. JavcB, (1828) ; Endlicher Meletemata, p. 10. (1832). 
j Essential Character. — Parasitical leafless plants. Stem, homogeneous. Vascular 
system scarcely present. Flowers propagated by the agency of sexes. Seeds having no 
embryo, but consisting of a homogeneous sporuliferous mass. 
At this point in the Vegetable Kingdom, we have reached the limit be- 
tween sexuality and asexuality at a different but similar road by which we ar- 
rive at it through Gymnosperms. The latter resembling Exogens in all the 
organs of their vegetation, gradually passed into the higher Acrogens through 
Equisetum, Cycadaceae, and certain Coniferae, Here we have another most 
curious assemblage, which, with many of the peculiarities of Endogens, seems 
to be an intermediate form of organisation between them and the lower Acrogens. 
They agree with Endogens in the presence of sexes, and sometimes in the ter- 
j nary structure of their flower ; but they have scarcely any spiral vessels 
I (vascular system), and their seeds appear, as far as they have been examined, 
I to consist of a mass of spores, and not to have any special embryo. In their 
succulent texture, in their colour, often in their putrid odour when decaying, 
in the sporuliferous seeds, and in their parasitical habits, these plants resemble 
Fungacese ; while in their flowers and their sexes they accord with Araceae 
or similar Endogens. 
Brown, however, values these circumstances differently. In the first place 
he looks upon Rafflesiaceae to be at least closely allied to Aristolochiaceae, 
by which it would seem as if he considered the approach of these plants was 
to Exogens, and not to Endogens ; and secondly, he attaches no importance 
to the homogeneity of the embryo, because the same structure he says exists 
in Orobanche and Orchidaceae. But with regard to Orobanche, that plant has a 
slightly 2-lobed embryo lying in a mass of albumen, so that I do not see how 
it can be brought into comparison with that of Rhizanths ; and as to Orchida- 
ceae, I do not know that we have any right to say that it is homogeneous ; we 
ought rather to say that its structure is unknown. Supposing, however, that 
it was homogeneous, yet one could hardly consider it analogous to a “ nucleus 
compositus e tela cellulosa, corpusculis sporidiiformibus e cellulis angulatis 
conflatis et massulis grumosis immixtis, fills tenuissimis eamndem particu- 
las connectentibus, farcta,” which Endlicher describes in Scybalium fungiforme, 
and which is taken as the type of the structure of the seeds of Rhizanths. I 
know not whether this is right or not, and it must always be remembered that 
it is at variance with the elder Richard’s description of the seed of Cynomo- 
rium ; but supposing it to be wholly erroneous, still it seems to me necessary 
to admit the distinctness of Rhizanths from aU other classes. For although 
they have to a certain extent a vascular structure, yet it exists in the smallest 
conceivable degree. Brown says he has found spiral vessels in Rafflesia {in 
which he had at first denied their existence), and in several other cases. Mar- 
tins also found them in Langsdorffia, in the form of bundles lying in the 
rhizoma, stem and branches, and Mohl in similar parts of Helosis, but in such 
smaU quantity compared to the mass of the plants, as to form a fact of no im- 
portance. For it is not here a question about the presence or absence of 
spiral vessels, but about their abundance. In Exogens or Endogens equally 
developed they would be most copious, and would exist in all the foliaceous 
