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