4. Psilotum, Swartz.

Rhizome short, creeping, branched; true roots wanting. Stem erect or pendulous, simple below, repeatedly dichotomously branched above; branches angled or flat. Leaves very minute, scale-like, laxly placed, trifarious or distichous. Sporangia (or synangia), coriaceous, almost globular, usually 3-lobed and 3-celled, rarely 2-or 4-celled, in the axil or attached below the fork of a minute bifid scale-like fertile leaf or sporophyll, which is either sessile or raised on a short petiole. Spores minute, oblong, curved.

A small genus of two species, widely distributed in the tropical and subtropical regions of both hemispheres. The New Zealand species bas the range of the genus.