CRYSTALS IN THE CELLS OF PLANTS. 6^ 



In Fungi and Lichens the crystalline granules are commonly small and de- 

 posited not in the interior of the cells, but on the outside of the cell-walls, 

 and frequently in such large numbers that the tissue of hyphae becomes opaque 

 and stiff in consequence. In some Lichens minute granules of calcium oxalate 

 are deposited in the cell- walls of the dense cortical tissue {Psorosma lenh'gerum, 

 De Bary). It is only exceptionally that crystalline deposits occur in the interior of 

 the cells of Fungi, as, for example, in the form of radiate spheres (sphere-crystals) 

 in the swellings of some of the hyphae of the mycelium of Phallus caiiinus ac- 

 cording to De Bary. 



Little or nothing is known of the occurrence of calcium oxalate in most Algi^, 

 in Muscineae, and in Vascular Cryptogams ; but it is found very abundantly in the 

 tissues of most Phanerogams. In Dicotyledons it often occurs in the form of 

 large beautifully perfect crystals in the cavities of cells {e. g. in the mesophyll and 

 leaf-stalk of Begonia, and the stem and root of Phaseolus) ; clusters of crystals 

 are, however, in this class much more commonly deposited in a nucleus of proto- 

 plasmic substance («?. g. in the cotyledons of Cardiospermum Halicacabimi), where the 

 separate crystals are completely formed only in the detached part. Sometimes 

 also (as in the hairs of Cucurbita) small, beautiful, and perfectly developed crystals 

 are seen enclosed in the circulating protoplasm. 



In Monbcotyledons, especially those allied to the Liliacese and Aroideae, the 

 crystals of calcium oxalate occur mostly in the form of bundles of long very thin 

 needles, forming the so-called Raphides, which lie parallel to one another in such 

 a manner that they usually more or less completely fill- up the generally elongated 

 cells. Needles of this kind are formed also in great quantities when the leaves 

 of many woody plants change their colour and lose water by evaporation in the 

 autumn, although absent during the period of vegetation. 



Where the crystals lie in the cavity of the cell, and this is usually the case with 

 Angiosperms, they are commonly, perhaps always, coated by a thin membrane, 

 which remains after the solution of the calcium oxalate, and must probably be 

 considered as a coating of protoplasm. This is also the case, according to the 

 older statements of Payen, even with the raphides, and according to the accurate 

 observations and statements of others, also in the larger single crystals and 

 clusters. 



In Dicotyledons calcium oxalate occurs apparently only rarely deposited in 

 the substance of the cell-wall ; Salms-Laubach (/. c.) names different species of 

 Mesembryanthemum [31. rhombeum, tigrinujn, laceru?7i, stramineiini, Lemanni) and 

 Sempervivum calcareum, in which fine granules or (in the case of Sempervivu?7i) larger 

 angular fragments of crystalline calcium oxalate are scattered through certain layers 

 of the outer wall of the epidermis-cells of leaves. 



The occurrence of crystals of calcium oxalate in the substance of the cell-walls 

 is, on the other hand, according to the same observer, of common occurrence in 

 Gymnosperms. They generally consist of numerous small granules of unrecognis- 

 able shape ; not unfrequently, however, also of well-developed crystals. In the 

 bast-tissue of all parts of the stem deposits of this kind are found in the Cupres- 

 sineae, Podocarpus, Taxus, Cephalotaxus, and Ephedra ; they are absent, on the 

 other hand, from Phyllocladus In'chomanoides, Gingko biloba, Dammara australis, 



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