Perennial herb with deciduous aerial parts. Rhizome ellipsoid, more rarely fusiform or subglobose, (2–)3.5–9(–19) mm long, (1.5–)3–4(–5) mm wide; roots numerous, descending, then usually becoming horizontal, proliferous. Leaves commonly 2 or 3 (sometimes 4); stipe (2–)6–17(–20) mm long, 80–100% of its length subterranean, stipe:lamina ratio 0.4–0.8:1, stipe bases persistent; lamina bright green to yellowish-green, heldat 45–75° from the ground, elliptic, flat to shallowly concave above, (9–)14–32(–37) mm long, (3–)5–9(–12) mm wide, length:width ratio 2.1–3.6:1, apex sharply acute, sometimes shortly apiculate, base narrowly cuneate; venation isodiametric marginally, elongate medially, with numerous secondary veins and blind veinlets; epidermal cells elongate with wavy or sinuous cell walls; stomata strongly aligned medially, partially aligned marginally. Fertile spike (29–)36–57(–85) mm long, with (6–)9–14(–19) pairs of sporangia, fertile spike:lamina length ratio 1.9–2.3:1. Spores (33–)34–48(–52) µm in equatorial diameter, trilete (sometimes alete in malformed spores), muri very thick, rather uneven and of variable thickness, lumina reduced to conical pits, granules or tapetal residue completely lacking. Fig. 3/2.
