24. Cactus setispinus, sp. nov.

Mamillaria Setispina Engelm. Mss.

Fasciculate and ascending, simple or branched at base, the stems
about 30 cm. high and 3 to 6 cm. in diameter, densely covered
with remarkably long stout spines: tubercles short and broadly
conical, with axillary wool: spines white. with black tips;
radials 10 to 12, widely spreading, very unequal, 10 to 34 mm.
long, slender and flexuous; central spines 1 to 4, more rigid and
much longer (20 to 50 mm.), the upper ones straight, the lowest
one longest and hooked (usually upwards) and often variously
curved and twisted: fruit obovate and scarlet 30 mm. long: seeds,
black and pitted. Type, Gabb 15 in Herb. Mo. Bot. Gard.

Rocky or gravelly soil, San Julio Canyon. and in the vicinity of
San Borgia, Lower California.

Specimens examined: Lower California (W. M. Gabb 15 of 1867, at
San Borgia; Brandegee of 1889, from San Borgia and San Julio
Canyon).

In his notes Mr. Gabb describes the flower as "large, 3 to 3.5
inches long, bell-shaped, of a beautiful purplish red color,"
concerning which Dr. Engelmann remarks "this would indicate a
Coryphanth, but the tubercles show no trace of a groove, and,
moreover, a withered remnant of a flower laterally attached (say
18 to 20 mm. long), so that I have no doubt that Mr. Gabb's
statement is founded on some error." It is very probable that
the flowers are scarlet and larger than Dr. Engelmann suggests.