The Gum Palm or Dioon spinulosum is the tallest cycad in the world and reputed to grow to about 12 metres. This would clearly be after a long passage of time! The genus is endemic to Mexico and is found in limestone areas growing on well drained slopes. The plant prefers good watering providing the drainage is adequate. This cycad does very well in Australian regions providing drainage criteria are met. It can tolerate infertile conditions and is well suited to limestone rich soils given its natural growing environment in Mexico.