A process for determining age of boojum trees from rate-of-growth measurements is described. "The age estimate...can be obtained by multiplying the inverse growth rate by the height of the plant." Tabular data

The author, professor emeritus at the UofA, began his extensive research on the boojum only after his retirement in 1966. He recounts his fascinating experiences of the next five years as he studied the plants in Sonora. Numerous photographs of the Idria columnaris