This is the most majestic tree of the genus. The stem reaches eighty or a hundred feet in height, and besides being rather thicker in proportion than in the last species, offers a remarkable character in being constantly more or less swollen near the middle or towards the top. The trunk is generally cylindrical to a height of forty or fifty feet, where it swells out to double its former diameter or more for ten or fifteen feet further, when it again diminishes and becomes cylindrical for about twenty feet to the summit. It is only when the trees have reached their full height or nearly so that the swelling commences. In a forest where they abound many may be seen of a large size, but quite cylindrical from top to bottom, while others present every degree of swelling from a just perceptible thickening to a most extraordinary enlargement. The column of air-roots in this species is six or eight feet high, forming a compact conical mass, the separate roots being more slender than in the _Iriartea exorhiza_. The leaves are very large, with the leaflets broadly triangular and much cut and waved, forming a very elegant and yet massive head of foliage. The leaf-olumn is very thick, much swollen at the base, and of a deep bluish green colour. The unopened spathes are lunate in shape and curved downwards, and the spadices are small and simply branched. The wood of this tree is very hard, heavy and black, and is used by the Indians for making harpoons and spears with which they hunt the cow-fish. The swollen part of the stem is sometimes cut down and made into a canoe, when one is required in a hurry; otherwise it is not made use of. The tree grows on the Upper Amazon and Rio Negro, on hill sides and on the banks of brooks and springs; and the Indians say that wherever it abounds sarsaparilla will be found growing near. A fruit is represented on the Plate of the natural size. [Illustration: Pl. XV. W. Fitch lith. Ford & West Imp. IRIARTEA SETIGERA. Ht. 20 Ft. ] PLATE XV. IRIARTEA SETIGERA, _Martius_. Pashiúba miri, _Lingoa Geral_. This small species has the stem from fifteen to twenty feet high, and varying from the thickness of a finger to that of the wrist, which it never exceeds. The stem is smooth and cylindrical, but distinctly ringed. The roots appear only a few inches above the ground. The leaves are pinnate, the leaflets elongate, triangular and cut at the ends. The column is short and cylindrical, and both it and the petioles are covered with short hairs or down. The spadices have long stalks and grow from beneath or from among the leaves; they are rather large and are simply branched. The spathes form sheaths at the bases of the spadices, and are persistent. The fruit is oval, of an orange-red colour, and about the size of the “hip” or wild rose fruit.