longer than the radials, the base nearly 2 mm. wide; all the
spines horny and black-tipped; flowers 3.5 to 5 cm. long with
very slender and constricted tube, saffron-yellow: fruit green
seeds large (3 to 3.2 mm, long and 2 mm. in diameter), obliquely
obovate and curved, smooth and brownish. (Ill. Cact. Mex. Bound.
t. 74. fig. 8, seeds) Type, Schott specimens in Herb. Mo. Bot.
Gard.

"On grassy prairies on the south side of the Babuquibari
Mountains," Sonora. Fl. July.

Specimens examined: Sonora (Schott of 1853-4).

Dr. Engelmann remarks that the seeds of this species are larger
than those of any other Mamillaria known to him.

42. Cactus recurvatus (Engelm.) Kuntze Rev. Gen. Pl. 259 (1891).

Mamillaria recurvispina Engelm. Syn. Cact. 265 (1856), not
Vries.
Mamillaria recurvata Engelm. Trans. St. Louis Acad. ii.
202 (1863).

Globose or depressed-globose, 7.5 to 20 cm. in diameter, simple:
tubercles ovate, deeply grooved, crowded, somewhat imbricate, 10
to 12 mm. long: radial spines 12 to 20, bulbous at base,
compressed, rigid, recurved or flexuous, 8 to 18 mm. long,
whitish or horny, interwoven with adjacent clusters; central
spine solitary (sometimes an additional upper one), stouter and
longer (12 to 20 mm.), dark, mostly strongly recurved and