Monographs Details: Asplenium auriculatum Sw.
Authority: Morton, Conrad V. & Lellinger, David B. 1966. The Polypodiaceae subfamily Asplenioideae in Venezuela. Mem. New York Bot. Gard. 15: 1-49.
Description:Species Description - Rhizomes erect, generally epiphytic but apparently also sometimes terrestrial; fronds few, the stipes rather long, gray-green, the blades yellow-green, herbaceous or somewhat fleshy, simply pinnate, 4-9 cm broad, the rhachis gray-green, the pinnae 8-14 pairs, horizontal, petiolulate, inequilaterally oblong, subfalcate, 2-5 cm long, obtuse to acuminate, the superior base auriculate, the auricle overlapping the rhachis, the lower base straight for 9 -11 mm, the upper margin with 6 -17 large, rounded teeth; veins all simple except those of the auricle or the lower ones once-forked.
Distribution and Ecology - Brazil (Bahia, Minas Gerais, Rio de Janeiro, Sao Paulo, and Parana) ; West Indies (Cuba, Jamaica, Hispaniola, Puerto Rico, and Guadeloupe), Venezuela (Aragua, Zulia) and perhaps Peru and Bolivia (doubtful specimens only seen).
Asplenium abscissum sensu Raddi. Opusc. Sci. Bologna 3: 291. 1819. non Willd., 1810.
Asplenium semicordatum Raddi. PI. Bras. 1: 36, t. 52. f. 1. 1825. Tvpe: Rio de Janeiro, Brazil, Raddi (isotypes FI, Fl-Webb). The isotypes show that this is a small form, with only 6 to 8 teeth on the upper margin of the pinnae, agreeing exactly with the type of A. auricularium Desv.
Asplenium auricularium Desv. Mem. Soc. Linn. Paris 6: 273. 1827. Type: Brazil, without collector (holotype P, Herb. Desvaux, photograph 4242). Desvaux cites A. tenerum sensu Raddi, with a query, but this is not the basis of his species; however, since there is such a close agreement between the specimens, it is likely that the Desvaux t\pe specimen was received by him from Raddi and is really an isotype of .4. semicordatum.
Type. Rio de San Francisco, Minas Gerais, Brazil, Freyreis (holotype S, not seen; isotype BM, photograph 7266).
The isotype in the British Museum shows a plant with exceptionally short and broad pinnae, only about twice as long as broad, and essentially obtuse at the apex; however, it does not appear to be separable from plants much smaller usually identified as A. semicordatum Raddi. The identity of A. auriculatum and A. semicordatum was recognized by early writers and also by Christensen, who, however, confused the nomenclature, and the confusion has remained uncorrected. Swartz' A. auriculatum was validly published in 1817, but Christensen rejected it in the Index Filicum in favor of A. auriculatum (Thunb.) Kuhn, which is a later homonym, dating from 1868; the reason was that the basionym of A. auriculatum (Thunb.) Kuhn, i.e. Caenopteris auriculata Thunb., dates from 1795, and is thus older than A. auriculatum Swartz (1817). But of course under the Code (and also under the Rules that Christensen was working under) the date of the basionym is not the relevant consideration; Asplenium auriculatum Swartz has priority in the genus Asplenium, and cannot be displaced by the later homonym A. auriculatum (Thunb.) Kuhn.
Although this species has usually been recognized as distinct from A. salici-folium L., the specific lines are hard to draw. In general, A. auriculatum can be distinguished by its smaller size (blades up to 9 cm broad rather than up to 20 cm), obtuse or acute or sometimes acuminate pinnae (but not long-acuminate and falcate), fewer and longer teeth (in A. salicifolium the teeth mostly 17-30 on the upper margin, and not reaching more than one-sixth the way to the costa), mostly simply crenate rather than doubly crenate segments, and shorter sori (doubtless correlated with the narrower segments).
There seems to be a good deal of variation in habitat. Most labels that have notes indicate that the species is an epiphyte, but apparently it also grows terrestrially, and there are also indications that it grows on rocks. Very likely it grows am where where there is abundant shade and humus. The texture is thick and herbaceous, perhaps even somewhat fleshy in living condition.