A common differentiation for woody plants is: does it bloom on old wood (when flowers are initiated the season before they bloom) or does it bloom on new wood (when flowers are initiated the same season as they bloom).
When viewing all these wonderful photos of cacti, I see the distinctness of flowers originating from the sides of the plant, or flowers emerging from the tops. Is this necessarily due to the same phenomenon? In other words, are flowers on the sides because they are initiated the previous season, and flowers at the top because it is the current season's growth?
And, are cactus flowers really initiated as I hypothesize, or do flower always initiate in the current season, irregardless of the age of the stem of origin?