Dr F. Unger oji the Formation of Crystals in Plants, 19 



Massa Carrara ; Karsten, vol. vi. p. 229. Translated in the Edinburgh New 

 Phil. Joumalf vol. xxi. p. 110". 38. On the volcanic formations of Naples, 

 Sicily, and the Lipari Islands, in the " Bulletin de la Socic^tc* Geologique de 

 France,*' vol. iii. p. 170. 39. Observations on the communications made re- 

 garding Sicily by M. C. Prevost, ibid. vol. iii. p. 175. 40. Observations on 

 the marble of Carrara and some fossils of the environs of Spezia, ibid. voL iiL 

 p. 179. 41. Observations made with M. Escher jun. on the porphyries of 

 the southern flank of the Alps, in the Canton Tessin, ibid, vol, iv. p. 103, and 

 326. — 1835. Geognostical Map of the country between Magdeburg and Kas- 

 sel, intended for the use of his students during the projected excursion in IB?*^. 

 To this list there is now to be added the first volume of Hoffmann's Posthu- 

 mous Works, from which the present memoir is taken, and which is devoted 

 to a treatise on Physical Geography. The second volume will contain our 

 author's views on the more general departments of Geognosy, and more espe- 

 cially on Volcanos. 



Upon the Formation of Crystals in the Cells of Plants. By 

 Dr F. Unger. 



Some authors have erroneously maintained that the crystals 

 which exist in plants are not to be found in the cellules them- 

 selves, but in the intercellular spaces. They may have fallen 

 into this error from the fact that these groups of crystals are 

 sometimes so voluminous that they very much disturb the cell, 

 and give it a bulk of at least six times its natural size. In ge- 

 neral, these crystalline cellules contain no other organic sub- 

 stances, though I have found in the Piper hlandum crystals, 

 mixed with numerous grains of chlorophylle, within the same 

 cell. Meyen was the first to discover these crystals in the epi- 

 dermic cellules, for, previous to his time, it had been supposed 

 that they were confined exclusively to the parenchymatous cells. 

 To the two plants, the Maranta Zebrina and the Tradescanfia 

 discolor, which he pointed out as presenting this peculiarity, I 

 can now add a third, viz. the Goodyera repens. At the same 

 time, it is true that it is usually in the parenchymatous cellules 

 that these inorganic bodies are found. They appear in all the 

 divisions of the vegetable kingdom, from the simplest algae (Nos- 

 toc muscorum, Conjerva crystallifera) to the highest organized 

 vegetables. It seldom happens that only one crystal is found 

 in the same cellule, though this peculiarity may be found in 

 the Papyrus Jntiquorum and the Ficus Bengalensis ; but much 

 more frequently, even in the plants we have named, each cell 

 contains many. In those plants which have aerial cavities, the 



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