Cylindrical and erect: tubercles crowded, conical, glaucous, with axillary bristles: radial spines capillary and very numerous, white and crisped, entirely covering the plant; central spines 4 to 6, rigid, straight and spreading, straw-colored, 8 to 12 mm. long: flowers equaling the tubercles, the yellow petals striped with red: fruit unknown. Type unknown. Referred to Mexico in general, but definitely known only from Coahuila. Specimens examined: Coahuila. (Palmer of 1880). There is a confusion of synonymy between this species and C. rhodanthus, both having been named Mamillaria lanifera. The earlier M. lanifera of Haworth, however, is clearly M. rhodantha of Link & Otto; and although Prince Salm-Dyck revived the name for the present species, the law of homonyms will not permit it to stand. The name proposed refers to the abundant display of capillary radial spines, which is probably the most notable feature. 29. Cactus palmeri, sp. nov. Cylindrical: tubercles crowded, glaucous, cylindrical (somewhat broadest above), about 4 mm. long, with dense axillary wool containing bristles: radial spines 25 to 30, very slender and white but rigid, about 5 mm. long, spreading or somewhat radiant, entangled with those of neighboring tubercles, and so covering the whole plant; central spines 3 to 5 (usually 4), more robust, erect or slightly divergent, brownish with darker tip, 7 to 8 mm. long: flowers small: fruit clavate and scarlet: seeds black and strongly pitted, 0.5 to 0.8 mm. in diameter. Type, Palmer 921 in U. S. Nat. Herb. San Benito Island, off the west coast of lower California. Specimens examined: Lower California, San Benito Island (Palmer 921 of 1889, reported as Mamillaria Goodrichii). Very closely allied to C. capillaris of eastern Mexico. 30. Cactus stellatus Willd. Enum. Suppl. 30 (1813). Cactus pusillus DC. Cat. Hort. Monsp. 184 (1813), not Haw. (1803). Mamillaria pusilla DC. Prod. iii. 459 (1828). A very common West Indian species, apparently differing from the variety only in the very much fewer (12 to 20) radial spines, although numerous specimens, both dried and living, were examined for additional characters. This difference, however, is so constant and striking that, taken together with the wide geographical separation, it should stand as varietal. 31. Cactus stellatus texanus (Engelm.). Mamillaria pusilla texana Engelm. Syn. Cact. 216 (1856). Mamillaria texana Young, Fl. Texas, 279 (1873).