Type : "Hab. In Demerara, Americae meridionalis; legit et communicavit amiciss. C. S. Parker. [...] This was discovered by our excellent friend C. S. Parker, Esq. of Liverpool, in one of the many herborizing excursions he made during his visit to Demerara. In the shape of the frond it comes nearest to the Cape
Ophioglossum nudicaule; but that is much smaller in size, and has no appearance of midrib, which is very observable in our plant. It is probably allied to the New Holland
Oph. costatum of Mr. Brown." [protologue].
Guyana, Demerara, 1827, C.S. Parker s.n. (LT:
E00564839 [désigné par Meza-Torres, Boletín de la Sociedad Argentina de Botánica 50(4):
627. 2015]; ILT [cités comme syntype par Meza Torres]:
K000589307 [photo:
P01653459],
E00413859; illustration originale:
t. 40A in Hook. & Grev., Icon. Filic., 1. 1831 [désigné comme type par R.T. Clausen, Mem. Torrey Bot. Club, 19(2):
142. 1938]).