About Dioon spinulosum Dyer ex Eichler
Dioon spinulosum Dyer ex Eichler can exceptionally reach up to 16 meters (52 ft) in height, but most individuals grow to between 3 and 6 meters (10–20 ft) tall. Mature specimens produce numerous leaves that measure 1.5–2 meters (4.9–6.6 ft) long, each holding between 140 and 240 leaflets. This species produces some of the largest seed cones among cycads; including the stem, seed cones reach almost 80 centimeters (31 in) in length and 30 centimeters (12 in) in diameter. In the wild, Dioon spinulosum occurs in just three locations across the Mexican states of Oaxaca and Veracruz. While it was more widely distributed historically, it now grows in the lowlands of the Sierra Madre Oriental mountains. It inhabits limestone hills and cliffs within tropical evergreen rainforest, found at altitudes between 30 and 300 meters (100 to 980 ft) above sea level. It usually grows in the forest understory, with only a small number of individuals growing tall enough to emerge from the canopy. In cultivation, Dioon spinulosum grows slowly, has moderate salt tolerance, and is cold hardy in USDA zones 9B through 11.
