Ophioglossum parvifolium Greville & Hooker.

Plants 3-8 cm tall. Rhizomes erect, very thick, with numerous fibrous roots, usually bearing 2 or 3 fronds. Common stalk grayish green on most parts from being buried underground, 1.5-3 cm. Sterile lamina elliptic or elliptic-ovate, 1-3 × ca. 1 cm, subfleshy, base shortly cuneate, margin entire, apex acute or rounded; veins indistinct. Sporophore 4-5 cm, arising from base of sterile lamina; spike short and thick, 1-2 cm, surpassing sterile lamina 1-2 times, apex acute; sporangia 10-18 pairs. Spore surface coarsely reticulate. 2n = 240-480.

The spore ornamentation of Ophioglossum parvifolium from Yunnan (sample in K) is minutely reticulate. More detailed palynological studies are required. Very recent collections from SE Taiwan may represent the Japanese species O. parvum M. Nishida & Kurita (see Knapp, Web Albums Pteridophytes Gymnosperms Taiwan; https:// picasaweb. google.com/116136418529949606360?feat=email; accessed 17 Jul 2012). This will key out as O. nudicaule but differs by the smaller sterile lamina, 0.5-1.5 × 0.3-0.7 cm, shorter spike, 7-9 mm, and minutely reticulate spores.

Whittieria hengduanensis Z.L.Liang & Li Bing Zhang (复网瓶尔小草 fu wang ping er xiao cao), a similar genus/species was described (Liang & Zhang, PhytoKeys 249: 31. 2024) and had been for a long time confused with Ophioglossum nudicaule. They overlap in geographical distribution. However, O. nudicaule has no persistent old leaf stalks at the base of the rhizomes and fewer roots per rhizome, and the sporophore base is not slightly attached to the trophophore. Importantly, they have different venation patterns with W. hengduanensis with complex-reticulate venation and O. nudicaule with common reticulate venation, although Wagner and Wagner (Flora of North America North of Mexico 2: 85–106. 1994) reported complex-reticulate venation for the North American O. nudicaule. It is unclear whether the materials from Africa (type locality), Asia, and the Americas of “O. nudicaule” represent the same species.

Slopes, meadows; 1800-4300 m. SW Sichuan, Xizang, C and NW Yunnan [N India, Nepal].