Despite the almost total lack of rain over the last few years, the cardon cacti seemed to be doing quite well. Many-armed, robust and very green, they had enough reserves to flower.
The photo above shows flowers at all stages, including a relatively fresh one from the previous afternoon. These pale blossoms atract birds, bats and insects throughout the 24-hour cycle. Many of these pollinators will also disperse the many-seeded fruits.