Prof. 6. Gulliver on the Raphides of British Plants, 13 



II. — On the Raphides of British Plants. By George Gulliver, 

 F.R.S., Professor of Comparative Anatomy and Physiology to 

 the Royal College of Surgeons. 



It appears to me that these Raphides are deserving of more 

 attention than they have yet received, both in relation to the 

 structure and economy of vegetables, and as affording a wide, 

 interesting, and scarcely cultivated field of research for the 

 chemical phytologist. The raphides may also be often useful as 

 diagnostic characters in systematic botany when others are not 

 available ; for example, a mere fragment of one of the Onagraceae 

 or of the Lemnaceae may be so surely distinguished, simply by 

 its raphides, from some of its near allies in other orders, that 

 this fact ought henceforth to be added to the description of the 

 orders just mentioned, independently of its value in other 

 respects. At present, I believe, the raphides have not thus been 

 used ; nor, indeed, do I know that they have been described in 

 the majority of the British plants in which they occur, or even 

 mentioned in Lemnacese and Epilobium before my notice of 

 them *. Though common in some orders, it is remarkable that 

 the raphides are so rare where they might be most expected, 

 that I have not a single note of their presence in young parts 

 of the stem, leaves, and flowers of British Oxalidacese, Umbelli- 

 ferae, Labiatse, Euphorbiacese, or Polygonaceae ; and even among 

 Crassulacese, no crystals were found in Sedum Telephium and 

 ;Si. acre. In old decaying or diseased portions of Polygonaceae, 

 and in many other orders, crystals are frequent; but on the 

 present occasion they are only noticed in young growing or 

 healthy structures. 



That raphides are part of the regular structure, useful in 

 the economy of certain plants, and by no means only a result of 

 chemical changes connected with decay, would appear from the 

 present observations. The remarkably constant abundance and 

 situation of the raphides in some species supports this view. 

 Thus, in Lemna trisulca the bundles of crystals are contained 

 within the cells of the parenchyma, but are so much longer in 

 L. minor as to extend beyond the cell-wall, and are very abun- 

 dant in both species ; while inZ,. polyrrhiza and in L. g'ibba the 

 raphides are comparatively scanty. They occur, too, in growing 

 parts of other plants, either in the cells or intervening spaces of 

 young leaves and of the pistils. In some orders, as Compositae, 

 the crystals are chiefly confined to the ovary and testa ; while they 

 occur indiscriminately in all parts of the plant in other orders, as 

 Onagraceae and Orchidaceae. Further research is much required 

 as to their precise office in the vegetable economy, though no 



• Ann. Nat. Hist. May 1861. 



