flower unknown: fruit obovate, red, 2 cm long: seeds reddish,
angular, smooth, 2 mm. long. Type unknown.

From San Luis Potosi to southern Mexico.

Specimens examined: San Luis Potosi (Parry of 1879; Eschanzier of
1891): also specimens cultivated in Mo. Bot. Gard. in 1892;
growing in same garden in 1893. Mamillaria impexicoma Lem.,
afterwards reduced to a variety, was based upon fewer radial
spines and no central. As the central is occasionally wanting in
connection with the most numerous radials, and present with the
fewest, such a form would have to be separated solely on the
absence of the central spine, and even in the original
description of impexicoma the central spine is only said to be
"sometimes wanting." It has been impossible for me to separate
the forms. It should be said that the fruit and seed characters
given above were taken front a specimen whose few radials and no
centrals would undoubtedly refer it to impexicoma. As yet we are
ignorant of the flower of C. corniferus. For discussion of
relationships see under C. scolymoides.

++ Central spines 1 to 4.

48. Cactus scolymoides (Scheidw.) Kuntze. Rev. Gen. Pl. 261
(1891).

Mamillaria scolymoides Scheidw Allg. Gart. Zeit. ix. 44
(1841).

Globose or ovate, 5 to 7.5 cm. high. subsimple: tubercles