RHODOSPERME^. 67 



mineral masses. Such are the corallines or Nullipores, the 

 humblest of which are simple incrustations covering rocks or 

 the stems of other Algoe ; nor can we determine their vegeta- 

 ble nature until we have subjected them to chemical exa- 

 mination. Acid will remove the mineral matter and leave 

 behind a cellular body, in form resembling the original mass 

 and in composition similar to many of the Algie, Thus their 

 nature is established. Under similar treatment the jointed 

 corallines will be found to be bodies of a similar nature. 

 Some of these are among the most beautiful of marine plants. 

 I speak of those of tropical countries, for this group is pecu- 

 liarly characteristic of the tropics, and those of our own 

 shores are few and not very beautiful. The shores of Aus- 

 tralia seem to be peculiarly rich in beautiful corallines ; some 

 forming fans, like our Padina, but rose-coloured ; others 

 triply pinnate, like the most delicate Callithamnion ; others 

 with whorled ramuli, like Charce, &c. 



The fructification of this sub-class is deserving of much 

 attention, and has been the cause of no small trouble to sys- 

 tematic botanists. We here find plants, seemingly furnished 

 with two sorts of spores, both fertile, both equally capable of 

 reproducing the species ; each always developed by itself, the 

 two being never found on the same individual, though both 

 have been found on different individuals of almost the whole 

 of the known species. Analogy forbids our regarding both 

 these organs as spores, of the same value, and formed by si- 

 milar agency. There is no such thing as two systems of 

 fructification among other plants. But we do find many 

 plants in which the species is propagated by two modes; 

 first, by the ordinary way of seeds ; and secondly, by (jemmcB 

 or buds, which, originating like ordinary buds, do not deve- 

 lope into branches on the parent, but drop off in a bud-like 

 form, acquire roots, and grow into independent plants. 

 Hence it has been held that the double fruit of the Rhodo- 

 sperms should be explained in a similar manner; the hud or 

 gemnmle being here reduced to its simplest form, consisting 

 of a single cell. But here, too, the spore or representative of 

 a seed is equally simple ; and thus it becomes a matter of 

 uncertainty, in the present state of our knowledge, to deter- 

 mine to which of the spore-like bodies the rank of spore, and 

 to which that of gemmule, shall be assigned. We are igno- 

 rant, at present, of the circumstances attending the formation 

 of these bodies : we must therefore take them as we find them 

 formed in the plant, and reason on the appearances presented 



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