CACTACEX. ll 
junioribus dense tomentoso-lanatis ; areolis orbiculatis villosissimis demum nudatis; aculeis 10-20 
rectis seu subinde curvatis robustis rigidis basi bulbosis albidis seu citrinis apice fuscatis, radi- 
alibus 9-16, (3-5 inferioribus lateralibusque equilongis robustioribus compressis, 7-11 supe- 
rioribus debilioribus teretioribus), centralibus 1-5 validis augulatis paulo longioribus pallidis 
citrinis seu rubicundis, singulo validissimo porrecto ; floribus in vertice tomentosissimo laxis 
flavis ; sepalis 16-22 lanceolatis, inferioribus ciliatis ; petalis 16-20 oblongo-lanceolatis versus 
apicem denticulatis mucranatis ; stigmatibus 6-10; baceca viridi. 
Sandy ridges in the valley of the Rio Grande, from El Paso to the Cajion; also at Eagle 
Spring, and on prairies at the head of the Limpia, Charles Wright : fl. in July.—A stately plant, 
by far the largest of the northern Mamillarie ; largest specimens before me, 7 inches high, 5 
inches in diameter without the spines. Tubercles loosely arranged, in the smaller specimens in 8, 
in the larger ones in 13 spiral rows, at base 3-1 inch in diameter, suddenly contracted and 
almost cylindric, 1-14 inch long, and 5-7 lines in diameter, spreading, ascending ; tubercles on 
the lower part of plant shorter, more conic, and somewhat imbricated. Groove very deep, with 
1-5 orbicular depressed or hemispherical warts or glands, of nearly a line diameter. Central 
spines 10-18 lines long, mostly yellow ; lower radial about 9-15, upper 5-10 lines long, when 
young mostly red at base, paler in the middle, and dark purplish-black at tip, sometimes 
yellowish ; when old, all the spines become ashy-gray with dark tip. Flowers 2 inches long, 
yellow, ovary 5-6 lines long. Young and small specimens have smaller tubercles, and about 6-8 
radial spines 6-9 lines long, with asingle straight or recurved much stouter central one, an inch 
long. 
M. Scheerii, from Chihuahua, is distinguished from our plant, according to Prince Salm’s 
description, by the shorter and fewer (8-11) radial spines, and the single ‘“‘much longer, one 
inch long,’’ central spine; it is globose, 3-4 inches in diameter; flowers of same size as ours, 
with apparently entire (?) sepals, and red-streaked yellow petals. The areole are described as 
naked, while in our plant we find the young ones very thickly covered with long wool, which 
disappears by age. Nevertheless, I consider ours only asa northern form of the Chihuahua 
species, with more numerous and stouter spines; which character very often distinguishes north- 
ern and southern varieties of one and the same species. 
18. M. Ropustispina, A. Schott in litt.: robusta, simplex seu ceespitosa; tuberculis magnis 
patulis subteretibus sulcatis; areolis magnis orbiculatis, junioribus dense tomentosis; aculeis 
radialibus 12-15 robustis rigidis, inferioribus robustioribus obscurioribus rectis seu deorsum 
curvatis, superioribus rectis fasciculatis paullo tenuioribus ; aculeo centrali singulo valido com- 
presso deorsum recurvato, subinde altero superiore rectiore adjecto, aculeis omnibus corneis 
apice atratis subpollicaribus ; floribus e basi tuberculorum juniorum villosissima campanulatis 
luteis; tubo supra ovarium ovatum constricto tenui, intus ad basin usque filamentoso; sepalis 
lanceolatis, inferioribus ciliolatis; petalis numerosis ; stigmatibus 9-10 patulo-erectis ; bacca 
viridi; seminibus magnis oblique obovatis circa hilum parvum lineare centrale curvatis fuscis ; 
cotyledonibus distinctis foliaceis. (Tab. LXXIV, fig. 8.) 
On grassy prairies on the south side of the Babuquibari mountains, in Sonora, 4. Schott : 
fi July.—A large plant, cespitose, perhaps from the effects of prairie fires, as Mr. Schott sug- 
gests. Tubercles nearly an inch long, and about an inch distant from one another; areole 31-4 
lines in diameter; spines 9-15 lines long, lower ones stouter but a little shorter than the upper 
ones, dark on the upper and lighter colored on the lower surface; central spines 1 or sometimes 
