Ophioglossaceae of the Hawaiian Islands

Clausen, Robert

The five Hawaiian species of Ophioglossaceae are not closely related to each other. Each must either have been derived from a species of some other region or have come unchanged from this other region. The preferred order of listing these species is Botrychium subbifoliatum, Ophioglossum petiolatum, O. concinnum, O. nudicaule, and O. pendulum ssp. falcatum. Since no two of these are more closely related to each other than to species which occur elsewhere, no evolution surely can be claimed on the islands. Each or its ancestors must have reached the islands separately. No interaction among the species seems to have occurred. The possibility exists that the two endemic species and the ssp. falcatum of O. pendulum may have evolved on the islands, but also these may be relics of populations which died out elsewhere, but survived on the islands. By the criteria already discussed, Botrychium subbifoliatum possibly is an archetypic species, surviving on the Hawaiian Islands, which may have come from North America. The ancestral continental population very likely gave rise to modern B. dissectum. Ophioglossum concinnum may be closest to the ancestor of modern O. engelmannii, O. costatum, and O. ellipticum. Similarly, the ssp. falcatum of O. pendulum may be closest to the population from which ssp. pendulum is derived. These two subspecies grade into each other. No distinct discontinuity justifies separating them as species.

Ophioglossaceae of the Hawaiian Islands

Series