Arachniodes Blume, Enum. Pl. Javae

Arachniodes Blume, Enum. Pl. Javae View in CoL 2: 241. 1828.

Arachniodes View in CoL is characterized by creeping rhizomes, 3- to 4-pinnate blades with free veins, and reniform indusia. The genus is most closely related to Polystichum View in CoL and Dryopteris View in CoL , but in Bolivia it is most easily confused with Lastreopsis View in CoL and Triplophyllum View in CoL ( Tectariaceae View in CoL ), which have the costae on the penultimate segments raised adaxially and catadromous blades ( vs. axes grooved adaxially and blades anadromous in Arachniodes View in CoL ). A genus of about 50 species, mostly in the Himalayas and China, with a few species in Africa and the Americas ( Christensen 1920, Morton 1960, Tindale 1961). Recent phylogenetic work on dryopteroid ferns has shown that A. denticulata View in CoL , a species occurring in Bolivia, belongs to Arachniodes View in CoL s.s., whereas two other neotropical species currently placed in the genus, A. macrostegia (Hook.) R.M.Tryon & D.S.Conant View in CoL (not in Bolivia) and A. ochropteroides View in CoL , form a clade with Olfersia ( Moran & Labiak 2015) View in CoL . They will be either combined under Olfersia View in CoL or given a new genus name pending further systematic studies (R.C. Moran & P. Labiak unpubl. data).