EXPLANATION OF PLATES. 67 
Pu. 50. Crrgus purus: 1, part of a rib with a flower ; 2, bunch of spines, and 3, seed of same 
plant ; 4-5, bunches of spines of another specimen ; 6, same, with flower just closed ; 7, fruit, 
and 8, seed of same. 
Pu. 51, Cereus Fenpiert: A vigorous head of a plant brought from El Paso. 
Pu. 52. The same: 1, top of a plant with flower-bud and flower from El Paso ; 2, fruit with 
few and stouter spines ; 3, seed of same; 4, fruit with numerous slender spines ; 5, seed of same; 
6, another form of seed. 
Pu. 53. The same: 1, flower from Santa Fé; 2, young bunch of spines; 3-12, bunches of 
spines of different shape and size. 
Pu. 54. Cernus potyacantuus in flower ; usual form with short spines. 
Pu. 55. The same: 1, part of a rib with a flower and a bud; 2-4, bunches of spines ; 5, fruit 
with a bunch of spines; 6, seed of same ; 7, fruit of another long-spined form ; 8, seed of same. 
Pu. 56, Cereus pavcrsprnus: 1, an entire plant ; 2, 5 bunches of spines ; 6, seed. 
Pr. 57. Cereus Eyartmanyt: 1, a head brought from Sonora by A. Schott; 2, young, and 
3-4, older bunches of spines of the same}; 5, fruit ; 6, seed of same; 7, seed of Dr, Parry’s ori- 
ginal specimen. 
Pu. 58. Cereus Bertanpiert: 1, part of a plant with flower and flower-bud ; 2-4, bunches of 
spines ; 5, fruit; 6, seed. 
Pu. 59. Fig. 1-11, Cereus PRocumsens: 1, a plant with flower-bud, flowers, and young fruit ; 
2-9, different bunches of spines ; 10, fruit; 11, seed. 
Fig. 12. Cereus rusperosus: seed. 
Pu. 60, Fig. 1-4. Cereus Emoryr: 1, a fruit; 2, a bunch of spines of this fruit; 3, another 
one twice the natural size; 4, seed. 
Fig. 5-6. Cereus VARIABILIS: 5, fruit; 6, seed. 
Pu. 61. Cereus aicanteus: 1, part of the rib of an adult plant with two bunches of spines ; 
2, a bunch of spines ; 3, part of a young rib of an adult plant collected in March ; spines very 
short and slender yet ; 4-5, bunches of spines of a young plant about eight inches bigh. 
Pu, 62. The same; 1, flower; 2, fruit ; 3, seed; m, side view of embryo, cotyledons a little 
open ; ”, front view of same. 
: Pu. 63. Cereus Greer a. cisMontanus: 1, a flower ; 2, a young plant raised from seed in the 
third year, showing the tuberous root. 
Pu. 64. The same: 1, lower part of a stem with the large tuberous root; half the natural 
size; 2-4, sections of the stem; 5-11, spines of different states of development and of different 
ages ; all four times the natural size; 5, a bunch of very young spines imbedded in the wool of 
the areola ; 6-10, full grown spines ; 10, shows the lower spines crossed ; 11, represents a very 
old bunch of spines; 12, a fruit; 13, seed. 
Pu. 65. Cereus Greaei, 8. TRANSMONTANUS: 1, flower ; 2-3, spines ; four times magnified. 
Pu, 66. OPUNTIA STENOPETALA: 1, part of a joint; 2, part of another one with two flowers ; 3, 
section of flower. 
Pi. 67. Opuntia Srriam: 1, an elongated joint with two fruits, bearing a young joint; 2, an 
orbicular joint ; 3, several seeds. 
Pu. 68. OPUNTIA FILIPENDULA: 1, a whole plant in flower, half natural size; 2, a joint with 
flower and young fruit, natural size; 3, seed of this plant from below El Paso; 4, seed of same 
from Dofia Ana, above El Paso, a little smaller. 
