Dioon spinulosum, giant dioon, or gum palm, is a cycad endemic to limestone cliffs and rocky hillsides in the tropical rainforests of Veracruz and Oaxaca, Mexico.[1] [2] It is one of the tallest cycads in the world, growing to 12m in height. The tree is found at low elevations to 300 m above sea level.[1]
Dioon spinulosum prefers well-drained soil with regular water. It will grow in soils containing few nutrients, in soils rich in limestone, and on slopes. It is hardy to USDA Zones 9B – 11.
Dioon spinulosum has pinnate leaves that grow to about 5–7 ft (1.5-2.1 m) in length and radiate out from the trunk. The 120-240 leaflets on each leaf are small and flat, have small thorns and taper to a sharp point.