Specimens examined: San Luis Potosi (Eschanzier of 1891).

++ Central spines 3 to 12.

54. Cactus conoideus (DC.) Kuntze, Rev. Gen. Pl. 260 (1891).

Mamillaria conoidea DC. Rev. Cact. 112 (1829).
Mamillaria strobiliformis Engelm. Wisliz. Rep. 113 (1848), not
Scheer (1850).

Ovate-conical, 3.5 to 10 cm. high, 4 to 7 cm. in diameter below,
with densely woolly vertex, simple: tubercles conical, about 12
mm, long, closely appressed-imbricate ("giving the plant the
appearance of a pineapple or cone"): radial spines 10 to 16, ashy
to white, straight and stout, 6 to 10 mm. long, the upper longer
(10 to 15 mm.); central spines 3 to 5, stouter, brownish-black,
10 to 16 mm. long, the two or three smaller ones erect-spreading,
the single lower one more rigid, porrect or deflexed, 15 to 20
mm. long: flowers 2 to 3 cm long and wide, deep purple: fruit
unknown. (Ill. DC. Mem. Cact. t. 2) Type unknown.

On rocks, Coahuila and Nuevo Leon to San Luis Potosi and southern
Mexico.

Specimens examined: Coahuila (Palmer 378 of 1882; Pringle 3117 of
1890): Nuevo Leon (Wislizenus of 1847): San Luis Potosi (Poselger
of 1851; Eschanzier of 1891).

55. Cactus potsii (Scheer) Kuntze, Rev. Gen. Pl. 261 (1891).