64 EXPLANATION OF PLATES. 
Pt. 6, Fie. 1-8. Mammrarta Granamt: 1, a single plant; 2-4, bunches of spines, with one, 
two, and three central spines ; 5, a tubercle and bunch of spines, magnified twice ; 6, a bunch 
of spines from Dr. Parry’s specimen from the Colorado, also magnified twice ; 7, a flower from 
A. Schott’s specimen from the Gila; 8 seed. 
Fra. 9-12, MAMILLARIA BARBATA: 9, a tubercle and bunch of spines, natural size; 10, bunch 
of spines, magnified twice ; 11, fruit ; 12, seed. 
Pu. 7. Mammnaria PHELLosPERMA: 1, a flowerless plant ; 2, a bunch of spines; 3, a tubercle 
with the axillary wool and bristles, and the terminal bunch of spines twice magnified ; 4-6, 
bunches of spines with one or more hooks, twice the natural size ; 7-8, fruits of different size ; 
9, , 
Pt. 8, Fra. 1-8. Mamrzarta Wrrentit: 1,a whole plant in fruit, from asketch of Mr. Moell- 
hausen’s ; 2, a young, and 3, an old tubercle with spines of the same specimen ; 4—6, spines of 
. @ specimen from the Copper mines, four from the older part of the plant; 7, fll wer; 8, seed. 
Fie. 9-14. Mammiarra Goopricum: 9, tubercle with spines; 10, bunch of spines, natural 
size ; 11-12, tubercles with the axillary wool and bristles, and the spines; 13-14, bunches of 
spines ; the last four figures are magnified twice. 
Pt. 9, Fig. 1-3. Maminarta MeracanTHA: 1, whole plant in flower; 2, fruit; 3, seed. 
Fre. 4-14. Mamrnnarra Heypert, var. appLanta: 4, upper part of plant in flower and fruit; 
5-6, different views of flowers ; 7, fruit; 8, seed, all from the same specimen from El Paso ; 
9-14, bunches of spines of different forms, of the same variety, from western Texas. 
Fig. 15-17: bunches of spines and seed of the var. HemIspHamRICA, from Matamoras. 
Fie. 18-20. Mamimnaria eumMirera: different views of tubercles and spines. 
Pu. 10. Mammiarra Ecurnus: 1, whole plant in fruit; 2-3, tubercles showing the groove 
and the wool on the basal areola; 4-7, bunches of spines of younger and older plants; 8-9, 
same, with the central spine curved ; 10, fruit ; 11, seed 
Pu. 11. MAminaria pectinaTa: 1, whole plant in flower; 2-3, different views of tubercles 
from the sides of the plant ; 4-7, bunches of spines ; 8-9, tabiathas from the flower-bearing top 
of larger plants ; 10, seed. 
Pu. 12, Fie. 1-16. Marinara TuBercuLosa: 1, a large specimen in fruit; 2-11, tubercles 
and bunches of spines of different specimens ; 2-3, from a young plant; 10, a very young tuber- 
cle ; all the tubercles exhibit the large mass of dense wool at base ; 12, flower bud; 13, flower ; 
14, fruit ; 15, seed of the same ; 16, seed of another specimen, smaller, and with smaller marks. 
Fie. 17-22. Mammiarta pasyacanTHa: 17-20, tubercles and bunches of spines of different 
seen 21-22, ints of the same. 
EXICANA: 1, a plant with several branches in flower; 
diffe rent b ialierelew with bunches of spines, the woolly grooves extending more or less 
down along the upper side of the tubercle ; 4, a bunch of spines ; 6, a fruit ; 7, seed. 
Pu. 14, MaMiubarta MAcRoMERIs in flower. 
Pu. 15. The same: 1, one of the largest bunches of spines; 2, one of the smallest ones; 3, a 
young tubercle not fully developed ; 4, a young, but full-grown tubercle, bearing the flower at 
the lower end of the woolly groove, far above the axil; a younger tubercle attached to it; 5, a 
ripe fruit with a few scales; 6 and 7, seeds of the daiyeint and the smallest kind. 
Pu. 16. Mammiaria rissurata: 1, a flowering plant; 2, petals; 3, nine tubercles of different 
size and age, and in different positions ; 3, a large tubercle from above ; 4, same from below ; 
5, same from the side; 6, a smaller one, with fewer divisions from above ; 7, side view of same}; 
