Fork fern sporophytes lack true roots, but have creeping subterranean rhizomes. They also lack true leaves but have a green photosynthetic stem containing vascular tissue xylem and phloem with scale-like leaves that lack vascular tissue.

Psilotaceae are represented in New Zealand by two genera, Psilotum (1 of) and Tmesipteris (4 of). Tmesipteris normally grow, as epiphytes on tree ferns, but are occasionally terrestrial, while Psilotum prefers warm ground and is common in thermal areas.