12 UNITED STATES AND MEXICAN BOUNDARY. 
2, stouter, but not much longer, than the others; base of lower or principal central spine nearly 
one line wide. Flowers, 14-2 inches long, well characterized by the slender tube, which is con- 
tracted above the ovary, and quite similar in that respect to the flower of UM. spheerica (see 
above); petals ‘‘saffron yellow’’; filaments from the base of the tube, leaving no naked space 
above the ovary, as is the case in most species. Seeds 1.5-1.6 line long, and fully a line in 
diameter, the largest of any Mamillaria examined by me; albumen more distinct than usual in 
this genus; embryo curved, with somewhat foliaceous accumbent cotyledons, resembling much 
more the embryo of some Hchinocactus than that of any Mamillaria known to me. The plant is 
evidently nearly allied to the foregoing, and also somewhat to the last species, but is distin- 
guished by the very stout spines, and especially the slender and constricted tube of the flower. 
In XM. Scheerii the filaments leave the lowest part of the tube free. 
14. M. RECURVISPINA (sp. nov.): simplex, globosa seu depresso-globosa; tuberculis ovatis 
obtusis profunde sulcatis confertis subimbricatis; areolis obliquis ovatis; aculeis radialibus 12- 
20 basi bulbosa compressis rigidis recurvis flexuosisve albidis seu corneis apice swpe adustis 
intertextis; aculeo centrali singulo (interdum secundo superiore adjecto) robustiore longiore 
obscuriore decurvato seu raro rectiusculo; floribus in axillis villosissimis tuberculorum juniorum 
subverticalibus majusculis flavicantibus extus fuscatis; sepalis lanceolatis acutis integris ; petalis 
erosis. 
Kastern parts of Pimeria Alta, in Sonora, especially in the. Sierra del Pajarito, A. Schott: 
fl. June to August.—Heads single, mostly depressed, ‘4-8 inches in diameter’ (a living speci- 
men before me has only 3 inches.) Tubercles in my: specimen in 13 spiral rows, 5-6 lines 
long, ovate, somewhat compressed from above; areole very oblique, ovate, 2-24 lines long, 
white woolly when young. Radial spines, in my living specimen, 14-16; in a dried one, as 
many as 20; according to Mr. Schott’s notes, 12-14. One spine is distinctly superior, and 
one inferior; the others are closely arranged along both sides of the areola, 4-9 lines long, 
upper ones often a little longer than the lower ones. Central spine 6-10 lines long, dark, 
mostly strongly recurved, adpressed, so that the plant can easily be handled without hurting ; 
much like M. compacta from the mountains west of Chihuahua, to which it bears a strong resem- 
blance. It seems to be fully distinguished, however, by the arrangement of the flowers » which 
in ours originate from the base of full-grown tubercles, and are scattered over the top of the 
plant, being pushed out by younger tubercles, bearing new buds; while, in the Chihuahua 
species, they come from the axils of young, just growing, tubercles, and are crowded on 
the densely woolly top. Flowers about 14 inch long, and of the same width; petals lemon- 
yellow, darker, and with a brownish tinge outside along the midrib. 
1s. M. PECTINATA, (sp. nov.): simplex, globosa; tuberculis e basi quadrangulata conicis, inferi- 
oribus abbreviatis, summis floriferis teretibus longioribus sulcatis; areolis orbiculato-oblongis ; 
aculeis 16-24 omnibus radiantibus plerumque subeequalibus seu summis fasciculatis longiori- 
bus, e basi bulbosa lateraliter compressa subrecurvis, pectinatis luteo-albidis demum cinereis 
apice swpe sphacelatis intertextis ; floribus e vertice tomentosissimo centralibus flavis ; ovario 
globoso ; tubo brevi amplo ; sepalis sub-30 acutis aristatis, exterioribus lanceolatis apice recur- 
vis, interioribus oblanceolatis adpressis ; petalis sub-30 pluriserialibus oblanceolatis seu inti- 
mis obtusis retusisve, omnibus herbaceo-aristatis ; stigmatibus 9-10 linearibus luteo-albis 
stamina longe superantibus ; hacca ovata viridi floris rudimentis coronata ; 
. * a er seminibus elongato- 
obovatis compressis levibus lucidis fuscis, hilo parvo ventrali, (Tab. XI.) 
