Rhizome structure and evolution in the ant‐associated epiphytic fernLecanopterisReinw. (Polypodiaceae)

摘要

GAY, H., 1993.Rhizome structure and evolution in the ant‐associated epiphytic fernLecanopterisReinw. (Polypodiaceae). TheLecanopterisrhizome is expanded or hollow, and is used as a nest by ants of the generaIridomyrmexandCrematogaster.The 13 species ofLecanopterisdisplay six rhizome forms, unequally distributed between two subgenera. SubgenusMyrmecopteriscomprises four species, each possessing a characteristic rhizome:L. mirabilishas a solid, arched rhizome, with the domatium between the rhizome underside and host trunk;L. sarcopusdisplays dimorphism between solid frond‐bearing axes and hollow, frondless side branches; the rhizome ofL. Crustaceais hollow but phyllopodia are solid;L. sinuosahas hollow rhizomes and phyllopodia. The architecture ofL. mirabilis, L. sarcopusandL. Crustacearesults in a compact, many‐layered domatium, butL. sinuosahas a tittle‐branched habit. Members of subg.Lecanopterisare completely hollow and have a compact architecture: six species typified byL. pumilahave a central gallery and hollow phyllopodia, and three species typified byL. darnaediihave two gallery and chamber systems. The genusLecanopterisis unlikely to be monophyletic; its nearest relative isPhymalodes.Phylogeny in subg.Myrmecopterisis unclear; no gradation of rhizome complexity exists. In subg.Lecanopteris, L. curtisiiis considered most similar to the ancestral species, giving rise to theL. pumilagroup, which engendered theL. darnaed