Lophosoria quadripinnata (
Lophosoria quadripinnata is a
The rhizome is massive, with hairs, not growing a trunk (not arborescent), and with radial symmetry instead of horizontal; a characteristic apparently originating in the ancestor of the tree ferns. The fronds are large in size, 2-3 pinnations, with hairs on the under side of the petioles, and they are high on its abaxial part, all common characteristics of the
Like all Polypodiopsidas, the sporangia are leptosporangiate (with a foot, capsule with a single-cell wall thickness, and dehiscent ring in the capsule). As in all the tree ferns, the ring is oblique and complete, not interrupted by the foot of the sporangium. The spores have trilete marks. This species has spores with a very unusual morphology, with a central belt ("cincture") that meant for a long time the species was assigned its own family, Lophosoriaceae.
The germination of the gametophyte corresponds to the Cyathea genus, giving rise to short strands of from two to six cells in both varieties. The prothallus development is of the Adiantum type. When raised in the laboratory, gametophytes of the quadripinnata variety are always chordates, however gametophytes of the contracta variety possess three morphs, depending on the density of spores that are developed (Dyer 1979). At low density, they are long spatulates with a central meristem and a slightly more developed wing than the other; at medium densities they are cordiforms and at high densities are band-like with a large amount of antheridia.