Isoetes nana sp. nov. (from the holotype: Ule 98, G). A1–4 Habit (images are courtesy of the herbarium G) B–D Megaspore B Proximal view of an obscurely cristate (B1) and rugulate (B2) megaspore C Distal view (<*portion of the megaspore covered by sporangium tissue) D Equatorial view E–G Microspore E Proximal view F Equatorial view G Distal view. Scale bars: A1–4 = 1 cm; B–D = 100 µm; E–G = 2 µm.