Psilotum complanatum
Psilotum complanatum Sw.
Psilotum complanatum, the flatfork fern, is an epiphytic fern ally in the Psilotaceae family. It lacks leaves and roots, with flat, triangular stems and dichotomous branching. The plant has protostele with a triangular xylem core and brownish rhizoids. It produces bean-shaped spores that germinate best in the dark with ammonium. The gametophyte is non-photosynthetic and relies on a fungal association. It grows from a subterranean rhizome.
Description
Psilotum complanatum is a rare herbaceous fern ally in the Psilotaceae family. It is epiphytic and lacks typical fern features like leaves and roots. The plant has flat, broadly triangular stems (5 mm wide) with dichotomous branching (1.5 to 2 mm wide). The stems have a triangular-shaped protostele and are covered with brownish rhizoids. Scales are arranged in two rows along the stems. Sporangia develop from the axils of small, bifid sporophylls. The spores are bean-shaped and monolete, germinating best in the dark with ammonium. The non-photosynthetic gametophyte depends on a fungal association for nutrients. The plant grows from a subterranean rhizome and reaches 10 to 75 cm in length. It is found in regions including the Bismarck Archipelago, Caroline Is., Colombia, and others.
Distribution
Desconocido · Bismarck Archipelago · Caroline Is. · Colombia · Cook Is. · Costa Rica · Cuba · Dominican Republic · El Salvador · Fiji · Hawaii · Honduras · Jamaica · Malaya · Maluku · Marianas · Mexico Central · Mexico Gulf · Mexico Northeast · Mexico Northwest · Mexico Southeast · Mexico Southwest · New Guinea · New South Wales · Nicaragua · Nicobar Is. · Peru · Philippines · Queensland · Samoa
Synonyms
Bernhardia complanataPsilotum intermediumPsilotum complanatum var. mexicanumPsilotum triquetrum var. complanatum
