Mamillaria sphaerotricha Lem. Cact. 33 (1839).
Depressed-globose: tubercles cylindrical, obtuse, with some axillary bristles: radial spines very much crowded, exceedingly numerous, radiant, very slender and bristle-like, white; central spines 6 to 10 and even more, erect and more rigid: flowers pale reddish: fruit unknown. Type unknown.
Referred to Mexico in general, but reported only from San Luis
Potosi.
Specimens examined: Mexican specimens from Hort. Dyck in 1857; from Hort. Pfersdorff in 1869; and growing in Mo. Bot. Gard. 1893 (from material sent by Pringle from San Luis Potosi).
++ The single central spine shorter than the radials (in C.
longimamma centrals often more than one and somewhat
longer).
34. Cactus gabbli, sp. nov.
Mamillaria gabbii Engelm Mss.
Globose, 5 to 10 cm. in diameter, simple: tubercles cylindrical, slender, 12 to 14 mm. long, with woolly axils: radial spines about 13, 5 to 8 mm. long, lower ones longer and stouter, especially the lateral ones pectinate; the central shorter, straight, and robust: flowers small, yellowish-red: fruit unknown. Type in Herb. Mo. Bot. Gard.
Among rocks, from San Ignacio to Mission San Fernando, Lower
California, and "perhaps farther north in the interior."
Specimens examined: Lower California (W. M. Gabb 19 of 1867).