Psilotaceae
Sporangia 2–3 (rarely 4), fused into synangia (Fig. 12), 2–6 mm in diam. or length, occurring in the axils of 2-lobed appendages. Sterile lateral appendages either minute and scale-like or leaf-like and 1–4 cm long. Stems simple or dichotomously branched. Rupestral or epiphytic plants Psilotaceae
Sterile lateral appendages 6–31 mm long; the apex mucronate. Synangia composed of 2 sporangia Tmesipteris
Apices of the majority of the sterile lateral appendages on each plant acute or rounded. Synangia rounded. Aerial shoots 5–16.5 cm long including the stems. Sterile lateral appendages almost equally-sided at the base
Apices of the sterile lateral appendages acute. Spores 60 µm diam. Widespread but not common. RF or tall open forests, epiphytic on tree ferns Tmesipteris parva
Apices of the majority of the sterile lateral appendages rounded. Spores 70–75µm diam. Widespread but not common. RF, epiphytic on tree ferns Tmesipteris ovata