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Mexico has an exceptional diversity of cycads within the Zamiaceae with three genera: Zamia, Ceratozamia, and Dioon. However, little is known of the ecological factors that explain their presence. Many of them grow under marginal conditions where water and soil are scarce. We studied the water requirement for germination of Dioon aff. merolae in San Jernimo Taviche municipality pertaining to Ocotln, Oaxaca, Mexico. We applied the same quantity of water but in five different watering schedules: (1) daily, (2) every other day (3) every six days, (4) every nine days, and (5) every 12 days. We used 50 seeds per treatment. After six months we calculated germination percentages and velocity with the Maguire index. The results show that, as irrigation frequency decreases, a lower percentage and speed of germination are obtained. This outcome opens new questions on the germination behavior of this Dioon species in its natural habitat.