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stouter brown ono strongly hooked (hook usually turned upwards), with often 1 or2 
straight upper ones in addition: flowers below the top, 18 to 24 mm, long, rose-col- 
ored; berry elongated and clavate, scarlet, 18 to 24 mm. long.—In the mountains near 
El Paso, its most eastern limit. 
5. M. Wrightii Eng. Depressed-globose, simple, 3.5 to 7.5 em. in diameter: tuber- 
cles terete, 10 to 12 mm. long, with naked axils: radial spines about 12, white, 8 to 12 
mm. long: central spines 1 to 3 (mostly 2 side by side), scarcely longer, divergent, 
with brownish and hooked tips (hooks usually turned downwards): flowers lateral, 
fully 2.5 cin. broad, bright-purple, with narrow acuminate petals: berry subglobose- 
ovate, purple, about 2.5 cm. long.— Near El Paso, which seems to be its eastern limit, 
and on the upper Pecos. 
+ + + A single straight shorter central spine, 
6. M. Heyderi Muhlenpf. Globose with a flat or depressed top, simple: tubercles 
elongated, pyramidal, subquadrangular: radial spines 10 to 22, straight, the lower 
ones longer; a single shorter central stout and straight spine: flowers lateral, red- 
dish: berry elongated-clavate.—From near Austin to Matamoras and westward to El 
Paso. Var. HEMISPHAcRICA Eng. has a convex top and 9 to 12 spines. 
7. M.meiacantha Eng. Verysimilarto the last, but with larger, more compressed, 
more loosely arranged tubercles, and fewer (5 to 9) stouter spines.—Common at San 
Antonio, southwestward into the great bend of the Rio Grande and westward into 
New Mexico. The central spine is often wanting. ‘The oblong scarlet berries, an 
inch or less long, are very good to eat” (Havard). 
8. M. spheerica Dietr. Proliferous and cespitose, single specimens clavate, but 
often forming dense hemispherical masses: tubercles elongated-ovate, acute, 12 to 16 
mm. long: radial spines slender, 12 to 14, 6 to 10 mm. long; asingle straight central 
one which is somewhat shorter and scarcely stouter; flowers 3.5 to 5 em. long, with 
yellow aristate-acuminate petals.—From Corpus Christi to Eagle Pass. Remarkable 
in this division on account of its exsert ovary and large flower. 
** Flowers larger and vertical, from the base of a groove on the young or nascent and 
spine-bearing tubercles: ovary exsert. ° 
+ Flowers yellow, 
9. M. Missouriensis Sweet. Simple or cespitose, proliferous, 2.5 to 5 em. in diam- 
eter: radial spines 10 to 17, slender, straight, frequently puberulent, white, 6 to 16 
mm. long; a single central stouter spine (often wanting): flowers 2.5 to 5 cm. long 
and wide, the fimbriate sepals and sparingly denticulate petals lanceolate or linear- 
lanceolate and acute: stigmas 2 to 8, erect or spreading : berry subglobose, scarlet, 
shorter than the tubercles. (MW. Nuttallii Eng.)—A northern species, extending from 
the upper Missouri to the San Antonio in Texas. Apparently not extending into the 
mountainous region of western Texas. The following varieties are the ordinary 
Texan forms: Var, C2srITOsA Watson is cespitose (forming masses often a foot broad), 
with 12 to 15 puberulent radial spines, central one generally wanting, 5 spreading 
stigmas, and larger flowers and berries. (MM. Nuttallii, var. caspitosa Eng.) Var. 
tOBUSTIOR Watson is almost simple, with longer and more loosely arranged tubercles, 
stouter and smooth spines, 10 to 12 radial spines and a solitary central one, larger 
flowers, and 7 or 8 spreading stigmas. (M. Nuttallii, var. robustior Eng.) 
10. M. Scheerii Muhlenpf., var. vatipa Eng. Almost simple, ovate-globose, 
glaucescent, large, 17.5 cm. high: tubercles remote and spreading, large, subecylin- 
drical, from a broad base, 2.5 to 3.5 em. long : groove very deep, with a few depressed or 
hemispherical warts or glands: younger areola densely woolly : radial spines 9 to 16, 
very stout (especially the lower ones), straight, bulbous at base, white or yellowish, 
dark at apex, 20 to 36 mm, long; central ones 1 to 5, stouter and angled: flowers 5 
em. long, from very tomentose young axils.—From Eagle Pass to El Paso, and on 
prairies at the head of the Limpia. ‘A stately plant, by far the largest of our north- 
ern Mamillaria ” (Engelmann). 
