184 INTRODUCTION TO CEYPTOGAMIC BOTANY. 



natives of the southern hemisphere. Wormskioldia san- 

 guinea, which extends north as far as the Feroe Islands, occurs 

 again at Cape Horn. Rhodymenia palTnata is one of the 

 best of the esculent seaweeds, but perhaps the most agreeable 

 form in which it can be eaten is simply as it comes from the 

 sea, when it forms a palatable article of food enough, where 

 other food is not be procured. All the efforts, however, of 

 M. Soyer cannot conceal in it, when cooked, a peculiar flavour 

 of lodiae, which is inseparable from Carrageen in any shape in 

 which at present it has come before me. A purple dye has been 

 prepared from it. Rhodymenia, Euthora, RhodophylUs, and 

 Oordyledadia, all afford species to our Nereis ; RJiahdonia 

 alone, of the North American genera, is unrepresented, and 

 that is confined at present to the north west shores. Worm- 

 skioldia sanguinea is so extremely like some of the Deles- 

 serice, especially those which occur in the southern hemisphere, 

 that at first sight it seems the most unnatural thing in the 

 world to separate them. But, similar as the fronds are, the 

 fructification is so completely dissimilar, that we must give up 

 the structure of the nucleus altogether, as affording distinctive 

 characters, if they are to be associated. In the former there 

 are elliptic spores by no means forming moniliform threads, 

 but separated into little rows by a peculiar tissue ; while in the 

 other there are beautiful moniliform threads, with the spores 

 sometimes forming their terminal joiats, sometimes radiating 

 at their base. It is, in fact, a most striking instance of analogy 

 without affinity. 



II. Desmiosperme^, J. Ag. 



Frond articulate or inarticulate, cartUagiaous, membra- 

 naceous or filiform ; nucleus consisting of tufted spore-threads, 

 arising from a placenta. Spores formed singly in each cell 

 of the sporethread, or only in the terminal cell. 



159. The first great division of Rhodosperms was distinguished 

 by the spores being ultimately disposed without order in the 

 nuclei, whether simple or compound. In the more typical 

 species this was evident enough, but in the early stage of 

 one or two genera, though the spores ultimately fell off, the en- 

 dochromes dividing into several distinct spores, before the 



