ILLUSTRATIONS. 



FACING 



PLATES PAGE 



PLATE i . Cactus Desert in Arizona Frontispiece 



PLATE 2. (i) Flowering branch of Pereskia pereskia. (2 and 3) Fruit of Pereskia pereskia. (4) Leafy branch of 



Pereskia sacharosa (5) Proliferous fruit of Pereskia sacharosa 10 



PLATE 3. (i) Flowering branch of Pereskia grandifolia. (2) Leafy branch of Pereskiopsis chapistle. (3) Leafy 



branch of Pereskiopsis pititache 20 



PLATE 4. (i) Upper part of flowering joint of Nopalea cochenillifera. (2) Upper part of flowering joint of 



Nopalea auberi. (3) Fruit of Nopalea auberi. (4) Flowering joint of Nopalea dejecta 34 



PLATE 5. Nopalea auberi as it grows near Mitla, Mexico 38 



PLATE 6. (i and 2) Branch of Opuntia mortolensis. (3 and 4) Branch of Opuntia leptocaulis. (5) Flowering 



branch of Opuntia arbuscula. (6) Flowering branch of Opuntia kleiniae 48 



PLATE 7. (i) Leafy branch of Opuntia kleiniae. (2) Terminal branch of Opuntia vivipara. (3) Branch of 



Opuntia parryi. (4) Flowering branch of Opuntia echinocarpa. (5) Fruiting branch of 



Opuntia versicolor 50 



PLATE 8. (i) Type plant of Opuntia vivipara, near Tucson, Arizona. (2) A much branched plant of Opuntia 



versicolor 52 



PLATE 9. (i) Joint of Opuntia tetracantha. (2, 3, 4, 5) Flowering joint of Opuntia versicolor. (6) Proliferous 



fruits of Opuntia fulgida 54 



PLATE 10. (i) Joint of Opuntia tunicata. (2, 3, 4, 5) Joint of Opuntia spinosior 66 



PLATE n. (i) Leafy branch of Opuntia imbricata. (2) Flowering branch of Opuntia prolifera. (3, 4) Form of 



Opuntia alcahes. (5, 6) Opuntia vestita.* 68 



PLATE 12. (i) Clump of plants of Opuntia fulgida. (2) A very open plant of Opuntia spinosior 70 



PLATE 13. (i) Opuntia exaltata as seen in the highlands of Peru. (2) Clump of Opuntia floccosa as it grows in 



the valleys of the Andes of eastern Peru 76 



PLATE 14. (i) Flowering branch of Opuntia burrageana. (2) Opuntia cylindrica. (3, 4) Joint of Opuntia stanlyi. 



(5) Flowering joint of Opuntia macrorhiza 78 



PLATE 15. (i, 2) Part of joint of Opuntia exaltata. (3) Upper part of joint of Opuntia macrarthra. (4) Upper 



part of joint of Opuntia tortispina 80 



PLATE 16. (i) Top of Opuntia miquelii. (2) Old and young joints of Opuntia invicta. (3) Upper part of joint 



of Opuntia ignescens 98 



PLATE 17. (i) Joint of Opuntia pascoensis. (2) Joints of Opuntia taylori. (3, 4) Form of Opuntia repen c . 



(5) Flower of Opuntia repens. (6) Flowering joint of Opuntia drummondii 102 



PLATE 18. (i) Two plants of Opuntia drummondii. (2) Joints of Opuntia retrorsa with flower. (3) Joints of 



Opuntia triacantha. (4) Joint of Opuntia jamaicensis. (5) Section of fruit of Opuntia 



jatnaicensis 104 



PLATE 19. (i) Plant of Opuntia jamaicensis. (2. 3) Flower of Opuntia jamaicensis. (4) Longitudinal section 



of flower of Opuntia jamaicensis. (5, 6) Stamen of Opuntia jamaicensis. (7) Style of 



Opuntia jamaicensis 112 



PLATE 20. (i) Flowering joint of Opuntia decumbens. (2) Frui ting joint of Opuntia decumbens. (3) Hybrid 116 

 PLATE 2 1 . Group of hardy Opuntia, mostly Opuntia tortispina, in grounds of New York Botanical Garden .... 126 

 PLATE 22. (i) Joints of Opuntia microdasys. (2) Flowering joint of Opuntia macrarthra. (3) Fruit of Opuntia 



macrarthra. (4) Seed of Opuntia macrarthra. (5) Flowering joint of Opuntia opuntia 128 



PLATE 23. (i) Flowering joint of Opuntia fuscoatra. (2) Upper part of joint of Opuntia sulphurea. (3) Joint 



of Opuntia tenuispina 132 



PLATE 24. (i) Plant of Opuntia santa-rita. (2) Plant of Opuntia discata 142 



PLATE 25. (i) Flowering joint of Opuntia atrispina. (2) Flowering joint of Opuntia phaeacantha. (3) Upper 



part of joint of Opuntia engelmannii 144 



PLATE 26. (i) Flowering joint of Opuntia bergeriana. (2) Flowering joint of Opuntia elatior. (3) Flowering 



joint of Opuntia boldinghii. (4, 5) Joint of Opuntia elata 152 



PLATE 27. (i) Upper part of fruiting joint of Opuntia schumannii. (2) Flower of Opuntia schumannii. (3) 



Flowering joint of Opuntia vulgaris. (4) Flowering joint of Opuntia stricta 156 



PLATE 28. (i) Flowering joint of Opuntia laevis. (2) Flowering joint of Opuntia dillenii. (3) L^pper part of 



flowering joint of Opuntia aciculata 1 60 



PLATE 29. (i) View of Opuntia keyensis. (2) View of Opuntia dillenii 162 



PLATE 30. Flowering joint of Opuntia linguiformis 164 



PLATE 31. Flowering joints of Opuntia lindheimeri. (i) Orange-flowered race. (2) Red-flowered race 166 



PLATE 32. (i) Upper part of flowering joint of Opuntia leptocarpa. (2) Fruit of Opuntia leptocarpa. (3) Flower- 

 ing joint of Opuntia velutina. (4) Upper part of joint of Opuntia megacantha 172 



PLATE 33. (i) Upper part of joint of Opuntia tomentosa. (2) Flowering joint of Opuntia brasiliensis. (3) 



Flowering branch of Opuntia brasiliensis. (4) Joint of Grusonia bradtiana 174 



PLATE 34. (i) Part of joint of Opuntia leucotricha. (2) Part of joint of Opuntia maxima. (3) Joint of Opuntia 



lasiacantha. (4) Joint of Opuntia robusta 180 



PLATE 35. (i) Plant of Opuntia fragilis. (2) Flowering branch of Opuntia rhodantha. (3) Flowering joint of 



Opuntia polyacantha 1 94 



PLATE 36. (i) Flowering joint of Opuntia spinosissima. (2, 3) Single flower of Opuntia spinosissima. (4, 5) 



Longitudinal section of flower of Opuntia spinosissima. (6) Cross-section of ovary of 



Opuntia spinosissima. (7) Style of Opuntia spinosissima 204 



