Sticherus retroflexus (J.Bommer ex Christ) Copeland (1947: 28)

Gonzales, Jasivia & Kessler, Michael, 2011, A synopsis of the Neotropical species of Sticherus (Gleicheniaceae), with descriptions of nine new species, Phytotaxa 31, pp. 1-54 : 43

Sticherus retroflexus (J.Bommer ex Christ) Copeland (1947: 28)

Gleichenia intermedia Baker var. flexuosa Baker (1887: 24) . Gleichenia retroflexa Bommer & Christ (1896: 657) .

Type:— COSTA RICA. La Palma, Pittier 1471 (holotype BR) .

Distribution and ecology:— Nicaragua, Costa Rica, and western Panama. On steep slopes along forest margins, landslides, and roadbanks, forming thickets in open disturbed sites, often mixed with other species of Gleicheniaceae , at 1100–2800 m.

Notes:— This species belongs to a group of four closely related species, which also include S. hastulatus , S. orthocladus , and S. intermedius . They all have scales restricted to the buds and rhizomes, hastulate, (in some species) short-petiolate segments, accessory segments on the pinna bases, 2- or 3-forked veinlets on the auriculate segment bases, obscure veinlets, abaxial blade papillae in most specimens, slightly to strongly undulate segment margins, and ovate, entire, translucent to slightly matte scales. All four species co-occur in Costa Rica and often form mixed populations. Morphologically they grade into each other, with S. retroflexus and S. intermedius as the most distinct forms and S. hastulatus and S. orthocladus as intermediate forms. It is conceivable that the latter are hybrids between S. retroflexus and S. intermedius , but more detailed studies are needed.