Onoclea sensibilis var. interrupta (sensitive fern, "Koyawarabi")

Japanese name: コウヤワラビ （高野蕨）
Scientific name: Onoclea sensibilis var. interrupta

[Overview]
A summergreen terrestrial fern commonly found in sunny, damp places such as the banks between rice fields.
The rhizome creeps for a long distance, and the plants often form colonies.
The fronds are of two kinds, sterile and fertile.
The sterile fronds are pale yellowish green to pale green, without scales or hairs, 8–30 cm long and 8–25 cm wide, broadly ovate to triangular-elliptic and once pinnately compound, with 5–11 pairs of pinnae.
The pinnae are lanceolate; those in the upper part have bases that run down the rachis to form wings, the margins are nearly entire or bluntly toothed, and the veins are netted.
The stalk of the sterile frond is 8–30 cm long and straw-colored, becoming brown at the base.
The fertile fronds are about as tall as the sterile fronds or slightly lower, and are twice pinnately compound; the pinnules enclose the sori and become spherical, and many are arranged along the pinna axis at intervals of 2–3 mm.
The sori are enclosed in a thin indusium.

[Notes]
The Japanese name comes from the fact that it grows abundantly on Koyasan.

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