Because button fern can tolerate periodically dry soil, an open terrarium will suit this plant just fine.
There is something about a small button fern ( Pellaea rotundifolia) that is terrifically appealing. Hailing from New Zealand, it's hardy and drought-tolerant. It is slightly mop-headed, but also kind of delicate and elegant at the same time. Because button fern can tolerate periodically dry soil, an open terrarium will suit this plant just fine.