264 M. Schomburgk on the Ant Tree of Guiana. n. 212. On Ranunculus Ficaria. Common. White, sporidia irregularly oblong, slightly curved. 136. Uredo Artemisia. Chev. Fl. Par. vol. i. p. 399 ; Berk. Brit. Fung. Fasc. 3.n. 235. On Artemisia Absinthium, King^s Cliffe. 137. Uredo pompholygodes, Schlecht. in Linn. vol. i. p. 248 ; Berk. Brit. Fung. Fasc. 3. n. 236. On Anemone nemorosa, King's Cliffe, May. It is to be observed that U. Ranuncula-cearum, Dec, is at least in great part the same species with the present, of which U. Anemones, Dec. Fl. Franc, is a sy-nonym. Consequently the species described in Eng. Fl. under the name of U. Ranunculacearum on Link's authority, must bear the name of Uredo Ficarice, Alb. and Schwein. XXVIII. — On the Ant Tree of Guiana (Triplaris Americana). By Robert Schomburgk, Esq.* TRIPLARIS, Linn. Class IX. Ord. II. Ord. Nat. Polygone^e, Juss. Flores dioici. Calyx basi tubulosus, pilosus. Flores Masc. Calyx limbo 6-partitus. Corolla 0. Stamina 9. Flores Fern. Calyx 3-partitus. Co-rolla 3-petala. Ovarium 3-quetrum. Styli tres. Akenium 3-quetrum, calyce aucto tectum. T. Americana, foliis alternis, integerrimis, oblongis, acutis, nervosis ; sti-pulis lanceolatis laceris, spicis terminalibus axillaribusque brachiatis. Triplaris Americana, Linn. Sp. PL p. 130. Aubl. Guian. ii. p. 915. t. 347.— T. Pyramidalis, Jacq. Amer. 13. t. 173. f. 5. A tree from fifty to sixty feet in height; its trunk smooth, of a greyish colour ; the branches erect, frequently in the form of a pyramid ; leaves entire, oblong and narrow, from nine to twelve inches long, of a dark green colour ; petiole di-lated at the base, somewhat amplexicaule, with ochreate sti-pulae, and marks at the opposite direction, as of fallen-off pe-tioles ; flowers unisexual. Males : calyx hairy, tubular, sur-rounded by a laciniated bractea, six-parted ; corolla absent ; stamens nine, divided in three parcels of different sizes, the large ones opposite the segments of the calyx, filaments somewhat crooked ; anthers ovate, two-celled, dehiscing lengthwise. Females : calyx provided with the bractea, three-* Read before the Botanical Society of London, April 6, 1838, and com-municated by that Society.