Noun | 1. | Helminthostachys - one species: terrestrial fern of southeastern Asia and Australia family Ophioglossaceae, Ophioglossaceae - a family of succulent ferns of order Ophioglossales; cosmopolitan in distribution flowering fern, Helminthostachys zeylanica - Australasian fern with clusters of sporangia on stems of fertile fronds fern genus - genera of ferns and fern allies |