120 On the Amylaceous Globules of the Floridese and Corallinese. 



a drop of sulphuric acid renders the globules violet, whilst the 

 envelope remains yellow ; the prolonged action of the acid dis- 

 solves the granules, and all that remains of the mass is a yellow 

 reticulated membrane, with circular or polygonal meshes, pro- 

 duced by a fold which the membrane sends between the globules 

 of the peripheral layer. A reticulated envelope of the same kind 

 exists also in Halopithys j but, the elements not hawng a strong 

 mutual adherence, it is torn under the knife, and is only met 

 with here and there in fragments carried away by the peripheral 

 globules, which are inserted upon it by small pedicels. I have 

 ascertained its presence in most of the species that I have inves- 

 tigated ; it is therefore very frequent, if not universal. 



The amylaceous formation which is clearly defined by the two 

 preceding examples, recurs with the same characters in the im- 

 mense majority of the Floridese and Corallinese, as is proved by 

 observations which I have already extended to more than thirty 

 species belonging to twenty-five genera. The difierences i-elate 

 to the mode of distribution of the globules in the tissues, and the 

 form and dimensions of the granules, which I have not as yet 

 found superior to those of Halopithys, and which are sometimes 

 scarcely O'OOl millim. I cannot enter here into the details of 

 these observations; but they explain why certain large species, 

 such as Iridaa edulis, Bory, which are very rich in this sort of 

 starch, may furnish a nutritive food to the poor inhabitants of 

 our coasts ; and at the same time they demonstrate in most of 

 the Floridese and Corallinese an abundance of amylaceous matter 

 which may be compared with that of the potato or the cereals. 



In the cellular Cryptogamia, starch in grains rendered blue 

 by iodine accompanies chlorophyll ; and its production appears 

 to be correlative with the mode of life, which results from the 

 functions of the green matter ; where the latter is wanting no 

 starch is found. The preceding observations acquire a fresh in- 

 terest by showing, in a vast group of cellular plants deprived of 

 chlorophyll and consequently endowed with an exclusively 

 comburant respiration, the formation of a principle very nearly 

 related to ordinary starch, but apparently not identical with it. 



Do these globules fill the vegetative cells at all periods of the 

 year ? and what is their part in the mode of life of these plants, 

 of which so little is yet known ? These are questions which I 

 shall endeavour to solve as soon as circumstances will permit. 

 M. Decaisne has been kind enough to verify the principal results 

 of this investigation, and I beg him to accept my best thanks 

 for having done so. 



