This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
1. Hard Carthagena Bark comes usually in pieces somewhat regular in shape, either completely or partially quilled, or flat, and frequently warped; the quills being from five inches to a foot long, from three to eight lines in diameter, and from half a line to a line and a half thick; the flat, somewhat thicker, about the same in length, and from one to two inches broad. But sometimes also it comes in small irregularly square or oblong, flattish pieces, variously warped, and mixed with small quills or fragments of quills. The epidermis is often absent, especially from the larger and flatter pieces, having been obviously scraped or pared off with a knife, and not separated, as in the Calisaya bark, by the natural juncture. When present, it is usually soft, whitish or yellowish, and of the character which has been called micaceous. The proper bark is of a pale, dull, brownish-yellow colour, often appearing as if rubbed over with the powder. Its texture is firm and compact; its fracture abrupt, though not smooth; its taste bitter and nauseous. It is derived from Cinchona cordifolia.
2. Fibrous Carthagena Bark is in quills, half quills, slightly rolled, or flat pieces, of dimensions and shape not materially different from the preceding, and like that coming generally in somewhat regular forms but sometimes in small irregular fragments. Some of the largest pieces exceed in thickness and other dimensions any that I have seen of the hard variety. The epidermis when remaining is soft, whitish or yellowish, and micaceous; but in the larger and (latter pieces it is generally absent, being artificially removed, as in the preceding. The proper bark differs much in character from the hard variety, being very fibrous, light, loose, soft, and spongy under the teeth. Its colour varies from a light brownish-yellow to an orange or red, the latter existing especially in the largest pieces. The colour of the powder is yellowish, often with an orange tint. The taste is usually bitter, but varies much in degree, being in some specimens strong, in others very feeble. The fibrous Carthagena bark bears considerable resemblance in colour to the Cali-saya, but differs greatly in its soft and spongy consistence, and in the circumstance that its epidermis has been artificially removed by the knife, instead of spontaneously separating at the natural junction. It is the product of Cinchona lancifolia.
3. Hard Pitaya Bark, or Brown Carthagena bark, as it has sometimes been called to distinguish it from the two preceding, which are sometimes designated as yellow Carthagena bark, is usually, as I have seen it, in small irregular pieces, either quilled or flat, from one to four inches long, and from one to four lines thick. The epidermis is sometimes whitish and soft as in the other Carthagena barks, but sometimes also dark brown, with innumerable cracks in different directions, giving the surface a grater-like appearance. Sometimes it is absent. Beneath the epidermis there is often a resinous layer, of a dark reddish-brown colour, and a shining surface when cut; but, though highly characteristic when present, it is wanting in some of the pieces. The proper bark is rather hard, compact, and heavy, closely and finely fibrous, and of a dull yellowish brown colour with a reddish tint. It somewhat resembles the hard Cathagena, but differs in the resinous layer, the graterlike epidermis of many of the pieces, and the deeper and redder colour. It has a very bitter taste. It is probably the product of the Cinchona Pitayensis of Weddell.