Today we bring you a gathering of crested old men (Cephalocereus senilis). We've gathered a fairly good collection of these hairy critters, just 'cause we like them. And they are really getting to be old men.
Crests, of course, are an abnormal growth of the apical meristem cells at the growing point of the plant. The normal plant grows straight up from a single point, while the crest develops a line of growth. The normal plant is below, a plant in our greenhouse:
We've had this plant for a number of years and most of the time it tends to get ignored as we go about our everyday chores. But it doesn't seem to mind.