One part of the leaf, the trophophore, is sterile and fernlike; the other, the sporophore, is fertile and carries the clusters of sporangia or spore cases.

One type of propagule is the ungerminated spores, which must percolate through the soil beyond the reach of light in order to germinate.

This presumably increases the probability that the spore will be in range of a mycorrhizal symbiont before it produces the tiny, roughly heart-shaped gametophyte, which also exists entirely below ground.

Mature sporophytes do not necessarily produce a leaf annually; they can remain viable underground for up to 10 years without putting up a photosynthetic component.

This feat is made possible by their dependence on symbiotic partnership with AM fungi of the genus Glomus, which supply most fixed carbon for growth and reproduction.