Abrodictyum C. Presl (Presl 1843)

Ahamada H. Saïd, Sabine Hennequin, Germinal Rouhan & Jean-Yves Dubuisson, 2017, Disentangling the diversity and taxonomy of Hymenophyllaceae (Hymenophyllales, Polypodiidae) in the Comoros, European Journal of Taxonomy 313, pp. 1-53 : 9

Genus Abrodictyum C. Presl (Presl 1843)

This pantropical genus comprises almost 25 species which are mostly terrestrial (and a few epiphytic) ferns displaying erect, large, highly-divided fronds on a short-creeping (or long-creeping in some Asiatic species) to erect stout rhizomes bearing numerous robust roots ( Fig. 4 ). All Comorian specimens represent only one species although they are identified as either A. rigidum (Sw.) Ebihara & Dubuisson or A. cupressoides (Desv.) Ebihara & Dubuisson. These two species are indeed commonly confused in collections. Kuhn (1868) also cited Trichomanes obscurum Blume (= Abrodictyum obscurum (Blume) Ebihara & K.Iwats. ) for Mayotte, but this species is in fact restricted to Asia and is clearly distinct even if also often confused with A. rigidum . Recent morphological and molecular studies focused on A. cupressoides and paleotropical A. rigidum evidenced that A. cupressoides is endemic to Seychelles and is in fact nested within the distinct genus Trichomanes ( Bauret et al. 2015) . Trichomanes cupressoides Desv. is thus absent from Comoros. Furthermore, specimens of the Malagasy region (including Comoros) formerly identified as A. rigidum actually represent a distinct species from the true neotropical A. rigidum ( Bauret et al. 2015) , and this new species has recently been described and named Abrodictyum pseudorigidum Bauret & Dubuisson (Dubuisson et al. 2016) .

Figures

Fig. 4. Terrestrial Comorian Hymenophyllaceae. A. Abrodictyum pseudorigidum Bauret & Dubuisson, first identified as A. rigidum (Sw.) Ebihara & Dubuisson, (F. Rakotondrainibe et al. 6771, P 00312031). B. Trichomanes boivinii Bosch, new for the archipelago according to the last inventories (as discussed in text) (F. Rakotondrainibe et al. 6675, P 00311390). Scale bar for both species = 3 cm.