形态特征：Plants aquatic, emergent. Root stock 3-lobed. Mi- crophylls white basally, green above, spirally arranged, widely spreading, 15–45 cm, ca. 3 mm wide at mid- length, in tufts of 50 to 120 (Fig. 1A), flattened on adaxial side, rounded on abaxial side (Fig. 1B), base expanded with white membranous margins, peripheral fiber strands present, central intrastelar canal 1. Lig- ule ovate-subtriangular, 3–5 × 1–2.5 mm. Sporangia with white membranous velum cover, basal, triangular- ovate, 8–12 × 3–5 mm (Fig. 1C). Megaspores gray when wet, white when dry, ca. 390–510 μm diam. (mean = 450 μm), with echinato-cristate ornamentation (Fig. 1D, E). Microspores gray in mass, elliptic, ca. 22–27 μm (mean = 25 μm) and ca. 16–20 μm wide (mean = 18 μm), echinate (Fig. 1F, G). Megaspores and micro- spores in different sporangia. Chromosomes: 2n = 22.
