HARDWICKE'S SCIENCE-GOSSIP. 



99 



in Science-Gossip of March, 1873, aud which the 

 French botanists called ' Crystal glands ' and 

 ' Cystoliths,' occur in several Moraceas and 

 Urticaceae. Raphides are found occasionally in the 

 same plant, together with either crystal prisms or 

 sphseraphides, or both, as may be seen, e. g., in some 

 Pontederaceas, Vitacese, Mesembryacese, and Me- 

 lanthacesB. 



Fig. 60. Tc, Sphseraphides, one in its cell, the other crushed, 

 from the leaf of the Nettle; /, Sph^eraphilles, one in its 

 cell, the other naked, from the stem of Mercurialis annua ; 

 m, the same, from the leaf of Silene maritima ; n, Sphfe- 

 raphid tissue (magnified less than half as much as the 

 other objects), from the leaf of Veratrum; o, Raphides, 

 from the same leaf. 



2. Taxonomic Characters. — As it would require 

 a volume to do justice to this part, it can be touched 

 but slightly here. Seeing the difficulty and fugacity 

 of many established botanical characters, and the 

 consequent perplexities of the student, it seems 

 strange that systematists should not be ready to 

 help him, by the use of any little contribution, from 

 whatever quarter, and however novel and unex. 

 pected. But they have hitherto totally ignored the 

 characters aiforded by raphides, although these are 

 eminently natural and constant, and often more plain 

 and permanent, fundamental and universal, than 

 some of the stereotyped diagnoses. In our flora, 

 raphides are so characteristic of the dicotyledonous 

 orders Onagraccae, Balsaminacese, and Galiacese, that 

 you might truly, and most briefly and sharply, define 

 Onagracese as Calycifloral Exogens abounding in 

 raphides; and so in like manner the other two orders. 

 Some "endogenous orders might be similarly cha- 

 racterized, while, on the other hand, there are orders 

 — Hydrocharids, e. ^.—regularly ex-raphidian amid 

 their allied orders which as constantly abound in 

 raphides. The Grape Vine and all its nearest allies 

 of the order Vitacese, of which the Virginian Creeper 

 is a familiar example, teem with raphides ; and this 

 character, frequently associated with sphseraphides, 

 is sufi&cient to distinguish the Vines from the other 

 orders of the Berberal Alliance. SLycn that most 

 curious plant Pterisanthes proclaims by its raphides 

 its af&nity with the Vines, and so does Leea, though 

 it has been removed from them by some eminent 

 systematists, and even erected into a distinct order 



by Von Martius. Among our common thick -leaved 

 window-plants, the Mesembryanthemums abound in 

 raphides, sometimes with minute prisms, and other 

 crystalline forms, in the same plant ; and though 

 this large genus is thus characterized, other 

 members, such as GUnus, of the same order, are 

 devoid of raphides, and hence show less relation to 

 Mesembryaceas than systematists have believed. 

 Raphides are plentiful in the Hyacinths. The 

 Caotacese afPord large sphajraphides and often a 

 profusion of coarse crystalline grit. The Jalap of our 

 Pharmacopoeia, being a Convolvulus, is quite devoid 

 of raphides ; and thus easily might it have been 

 distinguished from Mirabilis jalapci, of the order 

 Nyctaginaccas, in which they abound, and which 

 was so long and eiToneously supposed to afford that 

 drug. Though many Mouocotyledones are raphis- 

 bearing, several orders of them — the Grasses and 

 Sedges for example — are devoidof raphides. Sphsera 

 phides occur abundantly, and often very characteristi- 

 ca!ly,in the New Zealand Spinacli'of our gardens, and 

 in our native Goosefoot plants, in the Nettle or Hop 

 tribe (fig. GO, k), annual Dog's Mercury (fig. GO, I), 

 many members of the Silenal Alliance (fig. GO, m), the 

 Wayfaring-tree, Water-Milfoils, aud in numerous 

 different orders besides. The well-known crystals 

 in the Rhubarb of the Pharmacopojia are sphaera- 

 phides. Crystal prisms are plentifully produced by 

 many Monocotyledons, as may be seen in the common 

 cottage-garden favourite, Iris germanica, in the offi- 

 cinal sweet-scented Orris, in the bulb-scales of 

 the Onions (fig. G], r), and, among Dicotyledons, 

 in the Guaiacum bark and Quillaja (fig. 59, g) of 

 the shops. Either in the ovary or testa of our native 

 Cynarese and other Compositse, as may be seen 

 (figs. 59, h and i, and^Gl, p and q) in Serratula, Cen- 

 taurea, Carduus, Silybum, and the Inuleae, crystal 

 prisms are frequent, like to, but smaller than, those 

 of the foreign Quillaja ; and in some afford good 

 specific characters. Por example, the little long 

 prisms of Centaurea nigra (fig. 61, p) and C. cyanus 

 at once distinguish these species from C. scabiosa, as 

 in this last there are only those minute and short 

 crystals, cuboid, prismatic, flat, or lozenge-shaped 

 (fig. Gl, q), often each within a cell, which are so very 

 common in various orders of plants, especially 

 Amentiferae. The curious crossed and seemingly 

 truncate prisms of certain species of the Onions (fig. 

 61, r) are very characteristic. 



3. How tofindthe Crystals. — Of any plant already 

 cited as affording them, scrape and mash to a pulp 

 a bit of the leaf or other part in a drop of water 

 on the object-slide, then press with a thin glass 

 cover, and the crystals will be easily distinguishable 

 under an objective of half or quarter-inch focus. 

 Very delicate sections of the plant-tissue may be 

 needful to show the crystals uninjured in their 

 natural situation. Pulpy parts, like the berries of 

 the Arums and Black Bryony, and thin transparent 



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