Perennial herb with deciduous aerial parts. Rhizome fusiform to linear, (3–)7–11(–16) mm long, 1–3 mm wide; roots fleshy, horizontal, sometimes also descending, proliferous. Leaves 1 to 3; stipe (6–)12–20(–28) mm long, 80–90% of its length subterranean, stipe:lamina length ratio 0.6–1.4:1, old stipe bases not persistent; lamina bright green, appressed to, or held slightly off, the ground, broadly ovate, rarely narrowly ovate, usually flat, sometimes slightly folded along the median line, (9–)14–17(–24) mm long, (6–)9–14(–18) mm wide, length:width ratio 1.2–1.6:1, apex variable from obtuse to acute-apiculate, base broadly cuneate to truncate, margins flat and even; venation isodiametric laterally and distally, elongate proximally, secondary veins present with scattered blind veinlets, median band absent; epidermal cells elongate with sinuous anticlinal walls; stomata aligned medially only. Fertile spike (33–)50–82(–103) mm long, fertile spike:lamina length ratio 2.92–5.62:1, with (8–)11–14(–19) pairs of sporangia. Spores often undeveloped or variable in size with four diameter classes: 39–42, 48–50, 57–62 and ± 75 µm, trilete, muri irregular, commonly rounded, granulate, lumina reduced to narrow or subconical pits (see Note). Fig. 2/1 (p. 7).
