Asplenium

Kessler, Michael & Smith, Alan R., 2018, Prodromus of a fern flora for Bolivia. XXIX. Aspleniaceae, Phytotaxa 344 (3), pp. 259-280 : 259-280

Asplenium L., Sp. Pl. 2: 1078. 1753.

= Phyllitis Hill, Brit. Herb. 525, pl. 74. 1757.

= Antigramma C.Presl, Tent. Pterid. 120. 1836.

= Loxoscaphe T.Moore , Hooker’s J. Bot. Kew Gard. Misc. 5: 227. 1853.

Asplenium is characterized by small to medium-sized leaves, clathrate rhizome scales, nonarticulate petioles, usually free veins, and elongate sori, each with a narrow indusium borne on a vein. The otherwise often similar genus Diplazium ( Athyriaceae ) has similar sori, but in that genus they are usually placed back-to-back on veins. Asplenium is a nearly cosmopolitan genus of about 700 species and, with 81 currently known species, the second-most species-rich fern genus in Bolivia, after Elaphoglossum ( Dryopteridaceae ). It is found in almost all Bolivian life zones, except the driest ones, and often includes some of the most abundant fern species, especially in humid lowland and montane forests ( Poulsen & Nielsen 1995, Kessler et al. 2001, Schuettpelz & Trapnell 2006, Krömer et al. 2007).

Asplenium is taxonomically one of the most difficult fern genera in Bolivia. The delimitation of many species is based on few, variable characters such as the degree of blade dissection, rhizome scale characters, venation, and soral length/shape. Hybridization is common in temperate species ( Brownsey 1977, Matsumoto et al. 2003, Rumsey et al. 2004) and may also play a role in the tropics ( Yatabe et al. 2009), while polyploidy is also well known ( Perrie & Brownsey 2005, Shepherd et al. 2008, Hunt et al. 2011). Furthermore, apogamy appears to be common in some groups ( Murakami & Iwatsuki 1983), e.g., in A. auritum and allies ( Gabancho et al. 2010) and A. monanthes and allies ( Dyer et al. 2012, 2013). Particularly difficult species complexes in Bolivia are those surrounding A. auritum / A. cuspidatum , A. bangii , and A. radicans ( Weatherby 1931, Morton & Lellinger 1966). Many species of Asplenium reproduce vegetatively, most commonly via buds or plantlets borne toward blade apices; this means of propagation often results in dense clonal populations ( Mickel 1976, Koptur & Lee 1993).