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III. — The Sphmrai^hides in British Urticaceee and in Leonurus. 



By Professor George Gulliver, F.E.S. 



The sphaeraj)liicles in the leaf-blade of some Urticaceae are well 

 known, and have been described on tlie Continent as " crystal 

 glands " and " cystoliths." But there is another kind of sphaera- 

 phides in these plants which has hitherto escaped notice; and 

 though Mr. Eoj^er, in a late number of ' Science Gossip,' has made 

 some good observations on the sphseraphides in the leaf of the 

 wall-pelletory, the chemical composition of the two kinds of them 

 in all the British Urticaceae requires investigation. Nor have 

 we yet any descrij)tion of such crystals in Leonurus and other 

 Labiate©. 



In TJrtica dioica, U. urens, and Parietaria diffusa, the leaf- 

 blades are studded with sphaeraphides, each about ai^nd of an inch 

 in diameter, globose, smoothish or granular on the surface, and all 

 composed mainly of carbonate of lime. In the fibro- vascular 

 bundles of the leaf are chains of much smaller sphaeraphides, each 

 about ToVoth of an inch in diameter, rough from projecting crystal- 

 line points on the surface, and composed of oxalate of lime ; and in 

 the pith these small rough sphaeraphides are still more abundant. 

 Both the leaf and pith of Humuhis hipuhis abound in like manner 

 with the two kinds of sphaeraphides. In the leaf-blade these are 

 crystalline concretions, made up of glassy granules, consisting of 

 carbonate of lime. In the leaf-nerves, and in the pith of the stem, 

 are thickly-set strings of rough sphaeraphides, in shape and che- 

 mical composition like those in the same parts of the nettles and 

 pelletory. 



The sphaeraphides in Leonurus cardiaea seem to have escaped 

 notice, though they are very distinct. In other Labiatae 1 have 

 not yet met with similar crystals, much less raphides. The leaf- 

 blade of this plant is thickly dotted with globose granules, each 

 about o^oth of an inch in diameter, rounded in form, and contained 

 in a closely fitting cell, which is often tipped with a short uni- 

 cellular hair ; the globose crystalline matter consists chiefly of 

 carbonate of lime. In the fibro-vascular bundles of the leaf are a 

 lew much smaller rough sphaeraphides, each about aVooth of an 

 inch in diameter, and composed of carbonate of lime ; but the pith 

 of this plant contains no sphaeraphides. 



In all these examples the value of boiling the parts in a solution 

 of caustic potass is so great, that the crystals are exposed more clearly 

 than they appear before such treatment ; and sometimes, when not 

 easily found at first, the potass discloses them admirably, as may 

 be proved in the leaf of Ficus carica. Though this species is so 



VOL. XII. X 



