98 



HAflDWICKE'S SCIENCE-GOSSIP. 



an inch, and a thickness of soVoth. But they vary 

 much iu size in different plants, being very large in 

 the ofla.cinal Squill {Urgenia), very small in the Bed- 

 straws (Galiacese), and of intermediate size in the 

 Black Bryony {Tcmus communis). I have never 

 been able to find raphides in any British tree, though 

 they are plentiful in many foreign trees, as, e. g.^ 

 the Screwpines and Yines. 



Fig. 57. Raphkles : a, in the ovule of Fuchsia; b, in a 

 cell from the berry of Fuchsia; c, from the berry of 

 Arum maculdtum ; d, from the leaf of Neottia spiralis; 

 e, loose from the berry of Tamus communis; f, in an in- 

 tercellular space of an old [frond of Lemna trisulca. All 

 moderately maguified. 



Biforines, fig. 58, — Sometimes'the cell in which the 

 raphides are contained is soft and viscid, like a bit 

 of protoplasm, devoid of a distinct cell-wall, though 

 the wall, like Mohl's primordial utricle, may be 

 made apparent by chemical means. From such a 

 cell, as may be often seen iu some Aracese during 

 the microscopic examination, the raphides escape at 

 one or both ends (fig. 58); and hence the term 

 ' biforines ' by the Erench botauists. The pheno- 

 menon is singularly beautiful, for the brilliant and 

 hyaline crystals emerge from the cell with a life- 

 like activity that is quite surprising. 



Fig. 58. Biforines from Richardia cethiopica. 



Crystal Prisms (5gs. 59 and 61) are also acicular 

 forms, occurring either singly, or two or three 

 partly consolidated, never, like raphides, loosely in 

 bundles ; and each prism has several flat faces, and 

 as many angles ; the tips of the crystal appearing 

 sometimes truncate, more often pyramidal, with the 

 base of the pyramid corresponding to the shaft ; 

 and the end may be pointed, or like a carpenter's 

 chisel, or wedge-shaped, or sloped off obliquely from 

 angle to angle, or from face to face of the shaft. Of 

 the quadrangular prisms the faces may be all equal, 



or two of them broader than the other two 5 and of 

 the three-sided prisms a transverse section of the 

 shaft may present either an isosceles or equilateral 

 triangle. Occasionally the shafts are shaped as if 

 from a longitudinal cleavage, either partially or 

 completely, through the faces or angles of the 

 crystals. They are firmly imbedded in and along the 

 plant-tissue, and seldom or never in a cell that is 

 easily demonstrable. They are mostly larger, some- 

 times smaller, than raphides; and in Quillaja 

 saponaria about y^th of an inch in length, and 

 ysVoth in thickness. In the Shallot {Allium ascolo- 

 nicum) and someother Onions (fig. 61, r), the prisms 

 are shorter and thicker, often apparently truncate, 

 though sometimes plainly seeu with a low pyramidal 

 tip, having four sides ; the shafts either forming 

 crosses consolidated at the intersecting parts, or 

 occurring singly, varying much in size, and lying 

 across the tissue- cells. Iu the ovary and seed-coat 

 of Cynareee the prisms (fig. 59, h and i, fig. 61, p) 

 are much smaller, and frequently, as also in several 

 different orders, fused together longitudinally. 



r 



>& 



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esc 





Fig. S9. Crystal Prisms, highly magnified : g, from Quilluja 

 siiponariii ; li, from the testa of Silybum marianum ; i, 

 from the ovary.coat of Carduus lanceotatus. 



Sphcer aphides, fig. 60.— Each of these is usually a 

 rounded conglomeration of minute crystalline gra- 

 nules or angular crystals, frequently smoothish, often 

 granular or stellate on the surface, from projecting 

 granules or points of the constituent crystals, and 

 generally contained in a distinct cell (fig. 60). A 

 very common diameter of the sphseraphides is about 

 YoVoth of an inch each ; often smaller, especially in 

 several British plants ; much larger in others, and 

 larger still in some foreign species, such as the 

 Cactus-tribe. When the sphteraphides are regularly 

 spangled in a me'mbraniform part, consisting mainly 

 of their cells, I call it Sphajraphid Tissue (fig. 60, n) ; 

 and of tliis beautiful examples may be seen in the 

 leaves and inner layers of the bai-k of Aralia spinosa, 

 common on our lawns, in the sepals of the Purple 

 Loosestrife of our ditch-banks, and some wild 

 Geraniums, and in the leaves — with a profusion of 

 raphides — of Veratrttm nigrum. Sometimes each of 

 the spliseraphides appears as if suspended within its 

 cell by a pedicle (fig. 60, k), which is not always 

 easily seen : these, which Mr. Roper has described 



