26 



THE CACTACKAR. 



KEY To SPECIES continued. 



AA. Flowering areoles not confluent, though sometimes dose together, not forming a pscu- 



diH'cphalium continued. 



( ivary well-developed; flower-tube little scaly or without scales. 

 Flowering arcoles without wool, m wool very short. 



Fruit oblong to ovoid 14. ('. sniilliiinius 



Fruit globose or depressed 

 Spines acicular; berry large. 



Perianth-segments rounded, acute, or inucrouati-. 



Plant grayish green; at least the perianth-segments rounded 

 or mucronate. 



Outer perianth-segments rounded i.v ('. bnliiimrntis 



All perianth-segments rounded 16. ( '. ilivrhi^ii 



Plant glaucous green when young, dull green when old; outer 



perianth-segments acute. 

 Much branched, the branches ascending; ribs loto 13; style 



exserted 17. C. rubiiiii 



Little branched, the branches nearly erect; ribs 9 or 10; style 



scarcely exserted ; young growth very glaucous. 1 8. C. kcvrnsis 



Perianth-segments retuse i Q. ( '. monoclonal 



Spines subulate; berry small 20. 6'. scoparina 



Flowering areoles definitely long-woolly. 

 Ribs 5 to 13, separated by narrow valleys. 

 Ribs 8 mm. high 01 higher. 



Plant light green to dark green. 



Spines short, subulate 21. C. niorihitinits 



Spines slender, acicular. 



Wool of flowering areoles sparse, not matted 22. C. ttrrubiilae 



Wool of flowering areoles mostly copious, matted. 



Wool of flowering areoles brown 23. C. urban in n us 



Woo! of flowering areoles white. 

 Plant bright green, shining. 



Joints slender, dark green; wool short 24. C. nobilis 



Joints stout, light green; wool long 25. C. barbadensis 



Plant dull green, not shining. 



Wool elongated, up to 5 to 7 cm. long 26. C. millspaughii 



Wool short, 2 cm. long or less. 

 Ribs i to 2 cm. high. 



Only the flowering areoles woolly 27. C. swartzii 



Both flowering and flowerless areoles of young 



joints woolly 28. C. polygonus 



Ribs 8 mm. high or less 29. C. gaumeri 



Plant, at least young joints, blue or bluish green, glaucous. 

 Young spines yellow. 



Flower 7 to 8 cm. long 30. C. cltrysacanlhus 



Flower 5 to 6 cm. long. 



Ribs 6 to 8 31. C. maxonii 



Ribs mostly 9 to 12. 



Ribs 13 32. C. pianhyensis 



Ribs 9 or 10. 



Perianth-segments rounded or mucronate. 



Young joints bright blue; ribs low 33. C. lanuginosus 



Young joints bluish green, glaucous; ribs high. . .34. C. brooksianus 



Perianth-segments acute 35. C. royenii 



Young spines brown or nearly black. 



Areoles approximate, their spines overlapping 36. C. robitstus 



Areoles separated, their spines not overlapping. 

 Ribs 9 to 12. 



Wool short, 2 cm. long 37. C. comeles 



Wool 10 cm. long 38. C. leucocephalus 



Ribs 7 to 9. 



Ribs strongly horizontally grooved below the areoles. 



Flowers rose-red 39. C. sarloriunus 



F'lowers brown 40. C. palmer i 



Ribs not grooved ._ 41. C. tweedyanus 



Color of plant and of young spines unknown. 



Mexican 42. C. alensis 



Colombian 43. C. colombianus 



Ribs only 5 to 6 mm. high; plant green 44. C. purpitsii 



Ribs 4 to 6, separated by broad valleys. 



Glaucous, up to 10 meters high; flowers 6 to 8 cm. long 45. C. catingicola 



Bright green, up to 3 meters high; flowers about 5 cm. long 46. C. brasiliensis 



Ovary very short and flat; flower-tube scaly 47. C. phaeacanthits 



AAA. Species not grouped 48. C ulei 



