Mamillaria similis robustior Engelm. Pl. Lindh. 200 (1850).
Mamillaria nuttallii robustior Engelm. and Bigel. Pacif. R.
Rep. iv. 28 (1856).
Mamillaria missouriensis robustior Watson, Bibl. Index,
440 (1878).
Almost simple, with longer aid looser tubercles, 10 to 12 stouter
radial spines (6 to 16 mm. long), a single stout central, larger
flowers, and 7 or 8 stigmas. Type, Lindheimer of 1845 in Herb.
Mo. Bot. Gard.
From southeastern Colorado and the Canadian River (Oklahoma and
Indian Territory), to the Colorado River of Texas.
Specimens examined: Texas (Lindheimer of 1845, 1846; Bigelow of
1853): also specimens cultivated in St. Louis in 1847.
In Bigelow's specimens the central spine is mostly lacking.
40. Cactus scheerii (Muhlenpf.) Kuntze, Rev. Gen. Pl. 261
(1891).
Mamillaria scheerii Muhlenpf. Allg. Gart. Zeit. xv. 97 (1847).
Mamillaria scheerii valida Engelm. Syn. Cact. 265 (1856).
Ovate-globose, 7.5 to 17.5 cm. high, 7.5 to 12.5 cm. in diameter,
simple or sparingly proliferous at base: tubercles large (2.5 to
3.5 cm. long), from a broad base and suddenly contracted and
almost cylindric (10 to 14 mm. in diameter), deeply grooved (1 to
5 orbicular glands in the groove), distant, spreading and
ascending, the lower ones shorter, more conical and somewhat
imbricated, with broad axils and the younger densely woolly:
radial spines 6 to 16, straight or slightly curved, stout, rigid,
bulbous at base, whitish or yellowish (sometimes reddish) with
dark tip, the 2 to 5 lower and lateral ones stouter and
compressed (18 to 30 mm. long), the 4 to 11 upper ones weaker and
terete (10 to 20 mm. long); central spines 1 to 5, stout and
angled, 20 to 36 mm. long,,mostly yellow (sometimes reddish), a
single one very stout and porrect: flowers 5 cm. long, yellow
(sometimes reddish tinged): fruit ovate or subglobose, green:
seeds large (3 mm. long), flat and obovate, red. Type unknown;
that of the old var. valida is the Wright material in Herb. Mo.
Bot. Gard.
Sandy ridges, southwestern Texas, from Eagle Pass and head of
the Limpia to El Paso, and southward into Chihuahua, Coahuila,
and San Luis Potosi; also southern Mexico (fide Hemsley). Fl.
July.
Specimens examined: Texas (Wright 416, 478, of 1851, 1852; Evans
of 1891): San Luis Potosi (Eschanzier of 1891).
The var. valida was described by Dr. Engelmann without having
seen C. scheerii, the only knowledge of that species being
obtained from the description of Prince Salm-Dyck in Cact. Hort.
Dyck., which seemed to indicate a smaller form, with fewer spines
than the Texan form. However, when visiting the collections of
Prince Salm-Dyck, Dr. Engelmann found original specimens of C.
scheerii which were exactly his var. valida. So far as
collections show the Texan form seems to be more robust than the
Mexican, but the material is too scanty to justify such a
generalization. Dr. Engelmann speaks of this species as "a
stately plant, by far the largest, of the northern Mamillariae"
Its tubercles are bright green and in beautiful contrast with the
showy yellow spines.
41. Cactus robustispinus (Schott) Kuntze, Rev. Gen. Pl. 261
(1891).
Mamillaria robustispina Schott in Engelm. Syn. Cact. 265
(1856).
A large stout plant, simple or cespitose: tubercles large,
subterete, nearly 2.5 cm. long (and about the same distance from
each other): radial spines 12 to 15, stout and rigid, 18 to 30
mm. long, the lower ones the stouter, more dusky, straight or
often curved downwards, the upper straight and fascicled; the
solitary central spine stout, compressed, curved downwards
(occasionally an additional straighter upper one), not much
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.