40. Cactus scheerii (Muhlenpf.) Kuntze, Rev. Gen. Pl. 261
(1891).

Mamillaria scheerii Muhlenpf. Allg. Gart. Zeit. xv. 97 (1847).
Mamillaria scheerii valida Engelm. Syn. Cact. 265 (1856).

Ovate-globose, 7.5 to 17.5 cm. high, 7.5 to 12.5 cm. in diameter,
simple or sparingly proliferous at base: tubercles large (2.5 to
3.5 cm. long), from a broad base and suddenly contracted and
almost cylindric (10 to 14 mm. in diameter), deeply grooved (1 to
5 orbicular glands in the groove), distant, spreading and
ascending, the lower ones shorter, more conical and somewhat
imbricated, with broad axils and the younger densely woolly:
radial spines 6 to 16, straight or slightly curved, stout, rigid,
bulbous at base, whitish or yellowish (sometimes reddish) with
dark tip, the 2 to 5 lower and lateral ones stouter and
compressed (18 to 30 mm. long), the 4 to 11 upper ones weaker and
terete (10 to 20 mm. long); central spines 1 to 5, stout and
angled, 20 to 36 mm. long,,mostly yellow (sometimes reddish), a
single one very stout and porrect: flowers 5 cm. long, yellow
(sometimes reddish tinged): fruit ovate or subglobose, green:
seeds large (3 mm. long), flat and obovate, red. Type unknown;
that of the old var. valida is the Wright material in Herb. Mo.
Bot. Gard.

Sandy ridges, southwestern Texas, from Eagle Pass and head of
the Limpia to El Paso, and southward into Chihuahua, Coahuila,
and San Luis Potosi; also southern Mexico (fide Hemsley). Fl.
July.