EMPALEMENT one-leafed, above, tiled. Blossom of many folds. Berry of one loculament, many-seeded. SPECIFIC CHARACTER. CACTUS erectus, altissimus, maximus, sex-et octagonus, angulis distantibus, aculeos stellatos ferens. Calyx tubulosus, viridis: corollis radiatis, albis: petalis exterioribus læviter purpureis. Habitat in Surinamo. _Cactus hexagonus. Willd. Sp. Pl._ CACTUS with an upright stem, tall and large, six-and eight-sided, angles distant, bearing starry prickles. Empalement tubular, and green. Blossom rayed, and white: the outer petals slightly tinged with purple. Native of Surinam. REFERENCE TO THE PLATE. 1. A flower divested of the petals, and cut open to the base of the tube. 2. The seed-bud cut transversely. 3. One of the side shoots. 4. Miniature figure of the plant. No genus of plants more remarkable has yet been discovered than that to which our present subject belongs, whether we consider their simple succulent structure, strange diversity of form and habit, or the geometrical manner of their growth and disposition of their spines. Some of them, like the _Opuntia_ and _Ficus Indica_, grow like figs or cucumbers stuck one upon another; others, like C. curassavicus, resemble a little cushion stuck full of pins with the points outwards; the C. Melocactus and mammillaris are like melons covered with prickles: one, the moniliformis, has globular joints: the C. Tuna, (which Jacquin in his History of the Plants of America informs us is planted in the Island of St. Eustatius round their towns as fortifications,) the coccinilifer, and some others, have compressed ones: in C. Phyllanthus they are two-edged: we have Cactus triangularis, tetragonus, pentagonus, and the hexagonus now figured, but which varies occasionally from 6 to 8: we also have 7-8-9-10-14-and 15-angled species, even their spines are regularly disposed in quincunxes.