Mamillaria cornifera DC. Rev. Cact. 111 (1829).
Mamillaria impexicoma Lem. Hort. Monov. Cult. 5 (1839).
Mamillaria cornifera impexicoma Salm. Cact. Hort. Dyck.
20 (1850).
Globose, 7.5 cm. in diameter, simple: tubercles oblong-ovate, 2
cm long, crowded, the younger axils woolly: radial spines 15 to
26, rigid and horny, curved or sometimes straight, reflexed,
bulbous at base, yellowish (whiter with age) and with dark tips,
very sharp, 10 to 12 mm, long; the central one much stouter,
darker, slightly deflexed, 12 to 16 mm long, sometimes wanting:
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
conical, 10 to 16 mm. long, the upper elongated, incurved and
imbricate: radial spines 14 to 20, straight or often recurved,
white or horny, 10 to 20 mm. long (the upper the longer); central
spines 1 to 4, longer (18 to 32 mm.), more dusky, curved, the
upper ones turned upwards and intermixed with the radials, the
lower one stouter, longer, and curved downwards: flowers 5 cm.
long: fruit unknown. Type unknown.
From the Pecos River, western Texas, westward into southern New
Mexico, and southward into Chihuahua and San Luis Potosi.
Specimens examined: Texas (Hays of 1858): New Mexico (Bigelow of
1853): Chihuahua (Wislizenus of 1846): also specimens cultivated
in St. Louis in 1858.
Specimens collected by Mrs. Anna B Nickels across the Rio Grande
from Laredo, Texas, and showing neither flower nor fruit, seem to
intergrade between C. scolymoides and C. scolymoides sulcatus.
The habit is that of the former, the tubercles are those of the
latter, while the spines are somewhat different from either. The
number of central spines in these specimens is very hard to
determine, as on the adult tubercle they all assume a radial
position. The usual adult arrangement is an apparent absence of
central spines; 10 to 12 rigid, spreading and more or less
recurved radials (increasing in length from the lowest), which
are mostly white or the upper more or less dusky; and above, just
behind the radial row, 2 or 3 stout recurved-ascending spines,
which are white with tips more or less reddish-black, one of the
spines usually much stouter and longer than the others. This
form may represent a distinct species, but it seems very unsafe
to add species to the C. scolymoides group without the fullest
information.
Prince Salm-Dyck refers C. scolymoides to "M. daimonoceras Lem.
Cact. gen. nov., p. 5," but no mention of such a name can be
found in the work referred to. Labouret refers C. corniferus to
the same name and reference. If "M. daimonoceras" was anything
more than a garden or herbarium name used by Lemaire I have been
unable to find it, and Dr. Engelmann's notes indicate that his
search met with the same result. It is possible that the name
was applied loosely to this assemblage of closely related forms
that seem to cluster about C. corniferus.
A most perplexing question of relationship is presented by the
forms that have been called pectinatus, scolymoides, sulcatus
(calcaratus), Echinus, and the Mexican forms radians,
impexicomus, corniferus. It may be that they are all merely
varieties of one strong polymorphic type, but our knowledge of
corniferus is so incomplete, and material of other forms is so
scanty, that I can not venture to make such an assertion.
However, it seems probable that radians, pectinatus, scolymoides,
sulcatus and Echinus all have green fruit, while in impexicomus
and corniferus it is red. It has also seemed proper to merge
radians and pectinatus, also impexicomus and corniferus, and to
refer sulcatus to scolymoides as a variety. These seven forms
are thus reduced at least to four species.