Description
It is a small fern with pinnate fronds, growing in tufts, with a shiny reddish-brown stipe and rachis (stem and leaf axis). The fronds are dimorphic, with long, erect, dark green fertile fronds, which are deciduous, and shorter, spreading, lighter green sterile fronds, which are evergreen.
It does not spread and form new plants via the roots. The rhizome, from 1 to 2.5 millimeters (0.04 to 0.10 in) in diameter, bears a few narrowly triangular to linear scales, black to dark brown in color and strongly clathrate (bearing a lattice-like pattern). The scales are 2 to 4 millimeters (0.08 to 0.2 in) long and 0.3 to 0.6 millimeters (0.01 to 0.02 in) wide, with untoothed margins. The stipe (the part of the stem below the leaf blade) is 1 to 10 centimeters (0.4 to 4 in) long, and comprises one-quarter to one-third of the length of the blade. It lacks wings, and is a shiny reddish-brown throughout its length. Towards the base, it has a few threadlike scales similar in color to those of the rhizome.
The leaf blade is linear in shape, sometimes slightly wider in the upper half of the blade, measuring from 4 to 50 centimeters (2 to 20 in) long and from 2 to 5 centimeters (0.8 to 2 in) wide, sometimes as wide as 7 centimeters (3 in). It comes to a point at its tip and gradually tapers at its base. The blade is shiny and has a few scattered hairs, or lacks them entirely. The rachis (leaf axis), like the stipe, is reddish-brown or purplish-brown, shiny and hairless.
The blade is cut into pinnae throughout its length, from 15 to 45 pairs per leaf. They are rectangular or quadrangular in shape, those in the middle of the leaf blade measuring from 1 to 2.5 centimeters (0.4 to 1.0 in) in length and from 0.3 to 0.5 centimeters (0.1 to 0.2 in) in width. Each pinna has an obvious auricle at its base, pointing towards the tip of the blade and overlapping the rachis. The edges of the pinnae have rounded or small sharp teeth; they are more deeply cut in small forms. The tips of the pinnae may come sharply or gradually to a point.
Read more about this topic: Asplenium Platyneuron
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