Abrodictyum rigidum (Sw.) Ebihara & Dubuisson, Blumea

Kessler, Michael & Smith, Alan R., 2017, Prodromus of a fern flora for Bolivia. X. Hymenophyllaceae, Phytotaxa 328 (3), pp. 201-226 : 203

Abrodictyum rigidum (Sw.) Ebihara & Dubuisson, Blumea 51: 243. 2006.

= Trichomanes rigidum Sw., Prodr. 137. 1788.

Range: —Antilles; southern Mexico to Bolivia (BE, CO, LP, SC) and Brazil; related species occurring in Africa and Southeast Asia.

Ecology: —Common; terrestrial and saxicolous, in humid forests, often in ravines, rarely epiphytic or on fallen logs; 400–2650 m.

Notes: —Somewhat similar to, but smaller than, Trichomanes elegans (leaves 15–35 cm vs. 20–90 cm long), but Abrodictyum tends to be more finely divided (3-pinnate to 4-pinnate-pinnatifid vs. 2-pinnate to 3-pinnate-pinnatifid). Rachises are unwinged or very slightly winged; costae basally unwinged; proximal pinnae short-stalked; blades usually 1 cell thick; receptacles long-exserted; and living plants not iridescent.

According to Dubuisson et al. (2016), A. rigidum is most closely related to Asiatic and Pacific species, e.g., A. obscurum (Blume) Ebihara ; the single African species in this complex ( A. pseudorigidum Bauret & Dubuisson ) is nested in an Afro-Malagasy clade and not closely related to A. rigidum , as often assumed ( Moran & Smith 2001).