Page:Midland naturalist (IA midlandnaturalis01lond).pdf/197
On the obverse PILLEMV REX, and on the reverse BRVNING ON TANPI.
Bruning was a coiner, or moneyer, of Tamworth in the time of Edward the Confessor, and continued in the reign of William II.
Pitt mentions another silver penny of William II, having on the reverse IELFPINE ON TAM.
Raphides and Plant Crystals.[1]
By Mrs. G. R. Cowen.
Deposits of mineral matter in a crystalline form are frequently found in vegetable cells, where they are at once brought into view by the use of polarised light. They are commonly termed Raphides, or needle-shaped bodies, a term inappropriate to many of them, in which the crystals are of different forms, often prismatic or stellate,
As early as Malpighi's time, Raphides had been observed in plants, and at later periods they engaged the attention of Quekett, Lindley, Schleiden, and others, but they appear to have looked upon them as products of disease, or an accidental circumstance in the economy of the plant. The first to reduce to something like order, and to indicate the value of plant crystals, both as a constant and intrinsic result of the healthy life of certain plants, and also in determining the differences between species, was Professor George Gulliver, by whom they have been arranged in three groups, viz: Raphides, Sphæraphides, and Crystal prisms.
The crystals are mostly composed of oxalate of lime, sometimes with magnesia. In other instances the calcareous base is combined with tartaric, citric, or malic acid, and the acicular crystals usually consist of phosphate of lime.
Raphides are slender, needle-shaped crystals, with rounded smooth shafts vanishing at each end to a point. About ten to fifty or more lie parallel together, so as to form a bundle which partially fills a cell, or intercellular space. When undisturbed, this brindle lies along its cell, but the Raphides are so easily displaced by slight pressure that either all or part of them cross the cell in various directions, sometimes escaping from the ends. The raphis-cell is commonly very distinct, often oval, and contains some viscid, semi-fluid substance. in the midst of which lies the bundle of Raphides. The raphis-bearing plants among our native exogens belong to three orders, Galiaceæ, Balsaminaceæ, and Onagraceæ, and there is not a single instance of any species belonging to these orders without Raphides.
The Fuchsia belongs to the order Onagraceæ, and is a great raphis-bearing plant, quantities being found in the leaves, the berry-pulp,
- ↑ Abstract of a paper read by Mrs. Cowen before the Natural Science Section of the Nottingham Literary and Philosophical Society, on April 3rd, 1876.