Dioon spinulosum Dyer ex Each.

Giant Dioon or gum palm

This is one of the largest American cycads. It grows in the wild on limestone cliffs and rocky hillsides in tropical Mexico and is extensively cultivated as an ornamental. It is said to be fast-growing and can reach a height of 12m with a leaf length of 2m. It can be grown from seed which is said to be easy to germinate (unlike many other cycads). It can also be propagated from the ‘pups’ or offsets which develop around the base of the plant. The leaves have sharp spines along the margins as well as distinctive parallel veining.