This species is endemic to the Kasongo-Linda districts of eastern Democratic Republic of Congo. The climate is quite hot and humid. This is one of the largest cycads on the planet, and has longer leaves than any other species of known cycad. Leaves are green with somewhat wide armed leaflets. These leaves can grow in excess of seven meters and their fat stems can grow a staggering height of over fifteen meters (over hundreds of years)! Stems can be solitary, but on larger specimens it is more common to see them with basal suckers and large offshoots.
There are no cycads, that I can think of, that become larger or more impressive than this rapid growing species. Before this plant ever makes a foot of trunk, leaves will streak into the air, dwarfing much around them. The leaflets are heavily armed, but are pliable to the touch and are not overly pokey. The petioles are entirely different and possess very sharp, long spines and prickles. The growth habit of this plant is fairly erect, but can usurp more space as stems become large and more mature. Old specimens can easily be mistaken for palms as they are so large and tropical looking. In all areas, this species requites filtered light or shade. In the tropics or exceptionally humid areas, you can get away with growing this species in sun. They are susceptible to burn in drier areas and are not very frost tolerant (truly a tropical species of Encephalartos).
When I first got into cycads many decades ago, this was the hardest cycad in the world to acquire. A single seed sold for $25 to $50. We are quite fortunate to offer five to six year old 2 gallon plants on special. Caudexes are about 2 inches. This species wants plenty of room and an area where you don’t see much below a freeze.