Specimens examined: Texas(Schott 322, 614): New Mexico (Evans of 1891): also specimens cultivated in the Goebel Garden, St. Louis, in 1847, brought from "below Matamoras on the Rio Grande" by the St. Louis Volunteers, in 1816. On account of its convex top the variety becomes somewhat higher than the species (5 to 7.5 cm.), and the flowers are sometimes slightly longer (2 to 3 cm.). 7.Cactus meiacanthus (Engelm.) Kuntze, Rev. Gen. Pl. 260 (1891). Mamillaria meiacantha Engelm. Syn. Cact. 263 (1856) Hemispherical or with depressed vertex, 7.5 to 12.5 cm. in diameter, with a broad top-shaped base: tubercles compressed, 14 to 18 mm. long: radial spines 5 to 9 (usually about 6), stout and strongly subulate, 6 to 10 mm. long, straight or somewhat curved, whitish or yellowish, the lower mostly a little longer, the upper one sometimes wanting; central spine shorter and stout, darker, straight, and porrect, turned upwards among the radials, or rarely wanting: flowers 2.5 to 3 cm. long, reddish-white: fruit incurved, 2 to 3 cm. long. (Ill. Cact. Mex. Bound. t. 9, figs. 1-3). Type specimens are those of the collections of 1847, 1851, 1852, and 1853, from which the original description was drawn and all of which are in Herb. Mo. Bot. Gard. From the Guadalupe River, Texas, to the "Great Bend" of the Rio Grande, westward through western Texas and New Mexico; also northern Mexico (Hemsley); Fl. May, June. Specimens examined: Texas (Wright of 1851, 1852; Bigelow of 1853): New Mexico ("Missouri Volunteers" of 1847; unknown collector in 1880); also specimens cultivated in St. Louis in 1853, and others growing in Mo. Bot. Gard. 1893. Dr. Engelmann regarded this species as possibly only a variety of C. heyderi, to which it is certainly very closely allied through var. hemisphaerica, but the different tubercles and fewer stouter spines serve so well to distinguish it that it seems best to retain its specific rank. In reference to the citation of the original description an explanation seems necessary, which will apply to numerous similar cases. The Pacif. R. Rep. iv. 27 (1856), Syn. Cact. 263 (1858), and Cact. Mex. Bound. 9 (1859), have each been cited as the original publication. The confusion has arisen from the fact that in both the publications of 1856 the description in the Rep. Mex. Bound. is referred to, and in that report the plant is fully described as "sp. nov." However, the publication of the Boundary Report was long delayed on account of the preparation of the plates, and in the meantime both the publications of 1856 had appeared, in each one of which the species is distinctly characterized and reference made to the description in the forthcoming Boundary Report. As between the two publications of 1856 the Syn. Cact. (Proc. Amer. Acad. iii. 259) was evidently distributed first. 8.Cactus gummiferus (Engelm.) Kuntze. Rev. Gen. Pl. 260 (1891). Mamillaria gummifera Engelm. Wisliz. Rep. 21 (1848).