STRUCTURE,] NUMBER PROPORTION. 105 



The Leaves of multitudes of plants contain the various 

 kinds in great abundance ; Pisonia, Hemerocallis, and Calla 

 sethiopica furnishing the acicular, whilst Rheum palmatum and 

 undulatum are common examples yielding the conglomerate. 



The Stipules are not without Raphides, for those of the 

 Grape vine show them in situ, but very small in size. 



The Sepals of many Orchidacese abound with crystals, as 

 those of Bolbophyllum fuscum and others, and especially the 

 horny labellum of Catasetum. 



The Petals of many plants, like the sepals, contain more 

 or less crystalline matter, which is particularly evident in the 

 small corolla of the Grape vine. 



The Fruit does not so often contain them, yet the common 

 Grape furnishes a sufficient evidence of their existence in that 

 organ. 



In the Root their presence can be easily discovered, espe- 

 cially in all Rhubarbs, varying a little in number from the 

 locality of the specimen; most in Turkish, less in East-Indian, 

 and least in British-grown specimens. 



Number in a Cell. The number of Raphides in any cell 

 is subject to much variation. It is seldom that a single 

 crystal is met with; but in the Squill, Calla sethiopica, and 

 other examples, besides the multitude of acicular crystals, 

 some cells which are not dilated occasionally exhibit only one 

 minute rhombohedron, as has been observed by linger in 

 Papyrus antiquorum. Of the conglomerate kind, one cluster 

 is the usual number in the respective cells, though in Zamia 

 pungens two such can be at times observed within the same 

 cell. The acicular Raphides are in the greatest numbers, and 

 vary somewhat in quantity in different cells and in different 

 plants ; some containing but very few, whilst others contain 

 hundreds. 



Proportion to the weight of Tissue. The mass of crystalline 

 matter that is formed in the tissue of some plants is pro- 

 digious, whilst in others the quantity is very thinly diffused . 

 In several species of Cactacese the crystals equal if not exceed 

 the weight of dried tissue ; this is especially the case in Cereus 

 senilis. In Turkey rhubarb root, one hundred grains yielded 

 between thirty-five and forty grains of Raphides ; and the fact 



