THE POTTERY TREE OF PARA.

BY JOHN R. JACKSON.

(With a Plate.)

AMONGST Vegetable economic products the barks of various plants hold a prominent place, whether for medicinal, manufacturing, or other purposes. The structure and formation of all barks are more or less similar, though the contents of the cells vary much in different plants, thus we have soft or fibrous, hard or woody, and even stony barks, and the bark of the pottery tree of Para is a notable example of this latter. To outward appearance the formation of the bark in many plants would appear to bear no relation one with another, as, for instance, the cork of commerce compared with its near ally, the bark of the common oak, and again with the fibrous barks of many of our British trees. Naturally, the bark of a tree is, at first, composed of uniform cellular tissue, similar to the tissue of the central portion of the stem. The formation of the layers in the fully-developed bark is on the reverse system to that of the woody layers of the stem, the inner portion being the most vascular, and the outer portion the most cellular. Between the wood and the first formation of bark lies the cambium layer, a single series of nucleated cells, which originally are connected with both wood and bark, and perform certain functions in the formation of the woody fibres of the inner bark, and likewise in adding to the cells of the medullary rays of the wood. The innermost part of the bark next the wood, or rather next the cambium layer, is called the liber, or endophlæum; next to the liber, which is the fibrous part, the cellular part is placed, called the mesophlæum, or middle bark, and next that the epiphlæum, or outer bark. These three divisions are usually included under the general term of cortical layers. It is from the liber, or inner bark, which is composed of fibres more or less long and tenacious, that our most valuable commercial fibres are obtained.

In some plants the fibrous system prevails through the inner bark, but we shall have occasion to speak more fully upon these particular kinds at another time. What we have to deal with at present is a noted example of the harder, more woody, or more silicious barks, which example is to be found in the Para pottery tree. This is a large tree of very straight and slender growth, attaining a height of 100 feet before giving off any branches; the diameter of the base is seldom more than one foot, and rarely exceeds fifteen inches. The wood itself is very hard, and, as will be presently seen,

VOL. XII.-NO. I.

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