CACTACEA OF WHIPPLE’S EXPEDITION. 175 
Plate XV. figs. 1-4. Opuntia Missourrensis, var. TRICHOPHORA, E. & B.: 1, part of an old ‘stem showing the [56] 
thickness and hairy spines, Beda younger joints (unfinished); 2, bunch of spines hee a younger joint; 3, same from 
an = ‘sg of the plant; 4, fruit. 
OpuNTIA HysTRICINA, E. & B.: 5, a joint (unfinished); 6, a large bunch of spines; 7, fruit. 
Plate XVI. Opuntia Davis, E. & B.: 1, a branch showing the structure of the older parts, an older and young joints 
with two fruits; 2, a tubercle with its bunch of spines, the membranaceous sheaths partly torn, showing the spine itself; 
8, a degenerate sterile spiny fruit in its transition to a branch, as it is often seen in this species and others, especially cylindric 
opuntia ; 4, the whole 5a reduced. 
Plate XVII. figs OpunTIA WuHIPPLeEI, E. & B.: 1, a branch of the more common form of the plant covered with 
ripe ren —at (a) - it is undeveloped, probably not different from the ovary of the flower, only more shrivelled; 
2, branch of a larger specimen, spines more numerous, fruit larger; 3, a single bunch of spines of this specimen ; 4, whol 
plant reduced, 
igs. 5-6. OPUNTIA ARBORESCENS, E.: 5, a stout branch, with numerous spines and large fruit; 6, a bunch of spines 
of same, 
Plate XVIII. figs. 1-3. OpuNTIA ACANTHOCARPA, E. & B.: 1, an older branch with fruit; 2, a young branch; 
3, whole plant reduced. 
Fig. 4. OPUNTIA ARBORESCENS, E.: whole plant reduced. 
Figs. 5-10. Opuntia EcHINocARPA, E. & B.: 5, a branch of the plant densely covered with the sheathed spines ; 
6, 7, and 8, bunches of spines; 9, fruit, side view; 10, same, top view. 
Plate XIX. Opuntia Bicetovil, E.: 1, asingle joint; 2 and 3, tubercles, with bunches of spines; 4, young unde- 
veloped fruit; 5, an apparently full- grown fruit, mane and perhaps degenerating into a branch; 6, part of the ligneous 
skeleton, forming a wide tube, and show n the re structure the traces of the tubercles and branches; 7, an entire 
plant reduced, — on the left of the main pool isa eaaee sees with vigorous erect joints, 
Plate XX. OPUNTIA VAGINATA, E.: 1, an older joint, bearing two fruits, and a young vigorous shoot 
Figs. 2-3. OPUNTIA FRUTESCENS, E., var. LONGISPINA; from Williams’s River of the Colorado; 2, a branch with fruit ; 
3, lower part of the trunk, with some roots, — the sections show the structure of the dense wood 
Figs. 4-5. OPUNTIA FRUTESCENS, E., var. BREVISPINA: 4, a branch with fruits, most of them sterile, one producing 
young branches from its upper areola; 5, a flower. 
Plate XXI. OpunTIA TESSELLATA, E.: 1, a branch with fruit a a, and a withered flower 6; 2 and 3, flowers as they 
probably are reconstructed from withered specimens; 4, a small joint magnified so as to show distinctly the appearance of the 
tubercles and areole ; 5, part of the stem with a section of the wood above and a fracture below, so as plainly to show the 
ligneous structure, — the bark of the younger branches exhibits the tesselated surface, while in the older trunk it is lost in the 
irregular scales ; 6, ligneous skeleton of a young branch ; 7, a whole plant reduced. 
late XXII. figs. 1-8. Opunria cLavaTa, E.: 1, joint with a ripe fruit ; 2, one of the upper bunches of spines; 3, part 
of the me spine saagisthed 4 diameters 
. 4-7. Opuntia Parryi,. E.: ea joint with ripe fruit ; 5, bunch of spines, side view; 6, another one, front view ; 
7, part of a central spine magnified 4 diameters. 
The remaining figures of this and all the two following plates represent seeds and their ae of almost all the Opuntia 
deactitea i in sis report. Fig. a represents a Side view of the seed, natu ral size; b, same, 4 times magnified, as are all the 
following figures; ¢, posterior view ; d, anterior view; ¢, vertical section of seed, exhibiting the “sittin and proportion of the 
embryo and the ahineks J, embryo and sae coated by the maodlenn after the removal of the testa; g, lateral view of 
embryo. The other letters, h, 7, k, etc., will be explained wherever they occur. 
Figs. 8-9. Seeds of O. ENGELMANNI, var. CYCLODES. [57] 
Fig. 10. Seed of O. occrpenTALIS: one of the embryos, g, shows the cotyledons in an oblique, almost incumbent 
position. 
Fig. 11. Seed of O. ANGUSTATA. 
Figs. 12-15. Seeds of O. Camancurca, of different sizes and shapes. 
Plate XXIII. figs. 1-5. Seeds of O. rorTIsPINA : 1-3, seeds of different sizes and shapes ; 4, two akiceas in one seed ; 
h different views of both embryos together as they lay in the seed, 7 interior layer, and & exterior smaller embryo ; 5, germi- 
nation of a double embryo, — two young plants from one seed, the larger one still bearing the shell of the seed. 
Fig. 6. Seed of O. FUSIFORMIS 
Figs. 7-12. Seeds of O, Vistauetie and some of its varieties and sub-species : 7, usual form from Missouri (see Plate X. 
fig. 3), hik germination in different stages of development, 7 rr with three cotyledons, 
Fig. 8. Small seed from the fruit (represented on Plate X. fi 
Fig. 9. OQ. STENOCHILA 
Figs. 10-12. 0, cymocuita: 10 and 11, different forms of the usual variety ; 12, seed of the variety montana. 
Fig. 13. Seed of O. VULGARIS. 
