Plant with deep green foliage with serrated, spiny edges. This very large cycad (up to 16 m, with 2 m long leaves) is found only in eastern Mexico, where it is threatened with extinction due to its restricted distribution and the clearance of its native rainforest in many areas. Its scientific name describes the plant's appearance; spinulosum refers to its spiny leaflets (most other species in this genus have entire leaflets). The female cone of Dioon spinulosum is the largest cone of any gymnosperm, reaching 50-80 cm in length and 20-30 cm in width and weighing up to 15 kg. Each scale of the female cone has two seeds, hence its genus name Dioon meaning 'two eggs'. Many cycads have recently been found to contain carcinogens and neurotoxins with long-term harmful effects and the seeds of all cycads are more or less toxic.