160 RAPmDES AND PLANT CRYSTALS. 



and even in the ovrile. In this order, even the Beed-leaves, fragments of 

 stem, as well as parts stiU alive underground dm-ing the winter, may be 

 easily kno\vn by their Raphides from plants of other and closely allied 

 orders. 



None of our exogenous trees or shrubs have, up to the present 

 time, been found to produce Raphides, but they are present in many 

 exotic trees and shrubs of this class. In the order Vitaceaa, of which 

 the grape vine and American creeper are common representatives, we 

 find both Raphides and Sphseraphides in the leaves, young shoots, 

 ovaries, and ripe fruit. Our dictyogens abound in Raphides, as may be 

 seen in the Black Bryony and Herb Paris. In the former they appear 

 loose and destitute of a cell, both in the ripe berry-pulp, and the 

 root stock. This root is like a little yam, and the yams so commonly 

 used as food in the West Indies belong to this class, and contain 

 Raphides. 



The sarsaparilla of the shops affords Raphides, but not so the 

 American or false sarsaparilla, which is one of the AraUacesB, 

 abounding in Sphseraphides. 



In the other classes of our endogens, Raphides are more abundant 

 than in our exogeus. They are plentiful in the Hyacinth, the Star of 

 Bethlehem, the Cuckoo-pint ; also in the Lily of the Valley, the 

 Asparagus, and in the Daffodil and other Amaryllids. We find them 

 plentifully in most species of Duckweed, without the protection of a 

 proper cell waU, the boundary of the space being foi-med merely by the 

 outer walls of the contiguous tissue-cells. Raphides also occur in the 

 EngUsh Orchidacese. They vary in length fi'om l-27th of an inch to 

 l-500th of an inch. 



Sphasraphides are more or less rounded forms, made up of a 

 number of crystals, commonly opaque and whitish. They are generally 

 rough on the surface, from the projections there of the crystaUiue angles. 

 They vary very much in size in the same plant, and still more in different 

 orders, and ai-e universally diffused through Phanerogami a. Some 

 plants of the Cactus tribe, when aged, have their tissues so loaded with 

 them as to become quite brittle. The leave's or stem of the Hop, 

 Nettle, and many Goose-foot weeds, are good plants for Sphaeraphides ; 

 and so are the Begonias of our greenhouses. They are very large in the 

 Prickly Pear. 



Ciystal prisms are also acicular forms, but seldom occur more than 

 two, three, or four in contact, and then closely side by side, as if partially 

 fused together. They are more frequently strewed singly throughout the 

 plant tissue, and sometimes, as in the bulb-scales of Shallot, they form 

 crosses. They are generally larger than the Raphides, and can be plainly 

 Been to possess three or four faces or angles ; they do not taper at the 

 ends like the Raphides, but their tips are either pyramids, or like a 

 carpenter's chisel, or wedge-shaped, or the ends may be truncate, an 

 appeai'ance often caused by fracture. These crystals, when they lie in 

 contact, are not easily separable from each other, or from the tissue in 

 which they are seated, and when the cell can be seen it is closely 



