Abrodictyum tamarisciforme (Jacq.) Ebihara & Dubuisson

Dubuisson, Jean-Yves, Pechon, Timothée Le, Bauret, Lucie, Rouhan, Germinal, Reeb, Catherine, Boucheron-Dubuisson, Elodie, Selosse, Marc-André, Chaussidon, Cécile, Dajoz, Isabelle, Pynee, Kersley, Grangaud, Edmond, Robert, Yannis, Tamon, Jean- Maurice & Hennequin, Sabine, 2018, Disentangling the diversity and taxonomy of Hymenophyllaceae (Hymenophyllales, Polypodiidae) in the Mascarene archipelago, with ecological implications, Phytotaxa 375 (1), pp. 1-58 : 15-16

2. Abrodictyum tamarisciforme (Jacq.) Ebihara & Dubuisson ( Ebihara et al. 2006: 244), Fig. 7

Trichomanes tamarisciforme Jacq. (von Jacquin 1791[1789]: 285). Type:— LA RÉUNION. ‘Sponte crescit in insula Borboniae’, without date, without collector (holotype von Jacquin (1789): pl. 21, fig. 2). Note: The LINN specimen (LINN-HS1641-10) collected in La Réunion strongly resembles the illustration provided by von Jacquin, hence suggesting it could correspond to the original observed material.

= Trichomanes stylosum Poir. ( Poiret 1808: 82). ≡ Selenodesmium stylosum (Poir.) Copel. ( Copeland 1938: 81). ≡ Abrodictyum stylosum (Poir.) J.P.Roux ( Roux 2009: 38). Type:— MADAGASCAR. Without locality, without date, L.-M.A. du Petit-Thouars s.n. (lectotype P, P00482618!, here designated; isolectotype P, P00482633!).

= Trichomanes achilleifolium Bory ex Willd. (Willdenow 1810: 512), as ‘ achilleaefolium ’. Type:—“Ile de France & de Bourbon”, without date, J.B.G.M. Bory de St. -Vincent s.n. (lectotype B, BW 20 214010!, here designated; isolectotype P, P00477829 !).

Short description—Epiphytic, more rarely lithophytic ferns. Rhizomes short-creeping, with robust roots and clustered erect fronds, becoming more or less pendant in epiphytic specimens; fronds well stipitate, up to 50 cm long, usually lanceolate, less often oblong or ovate, appearing often falciform because of a curved rachis, usually bi-pinnate-pinnatifid, less often tri-pinnate-pinnatifid, and linear ultimate segments with usually 4(5) rows of lamina cells on both sides of the veins including a clearly distinct margin ( Fig. 7D ); sori numerous, paratactic, obconic, usually truncated or with a slightly dilated mouth; receptacle short to relatively long-exerted (up to 1 cm long).

Global distribution— Madagascar and Mascarenes.

Current distribution in Mascarenes— La Réunion, Mauritius.

Ecology—Usually epiphytic, often on tree-fern trunks ( Alsophila spp. ), less often lithophytic (especially on Mauritius), in the understory of rainforests, from low to middle elevations (250–1,700 m), more abundant in montane forests.

Specimens examined— MAURITIUS. Without locality, without date, without collector ( P01381686 ) ; without locality, without date, without collector ( P01381687 ) ; without locality, without date, P. Commerson s.n. ( P01485626 ) ; Pétrin, area above Black River Gorges , October 1974, Barclay 3329 ( MAU) ; Bar Le Duc , inside private hunting zone, December 2012, K. Pynee et al. s.n. ( MAU 0009261 ) ; Grand Bassin, Gouly Père Nature Reserve , October 2015, Gungadurdoss et al. s.n. ( MAU 0019238 ) ; Pétrin, State Land Raoul, next to road to Grand Bassin , February 2016, K. Pynee et al. s.n. ( MAU 0019004 , MAU 0019005 ) ; Brise Fer, Next Conservation Management Area , February 2016, K. Pynee et al. s.n. ( MAU 0011485 ) .

— LA RÉUNION. Plaine des Fougères , 1850, M. Boivin s.n. ( P01430194 ) ; without locality, before 1857, P. Commerson 1480 ( P00674943 ) ; without locality, without date, J. M. C. Richard 298 ( P01430186 ) ; Cilaos , November 1973, F. Badré 907 ( P01596683 ) ; Takamaka , May 1974, J. Bosser 22047 ( P01596685 ) ; Takamaka , May 1976, J. Bosser 22241 ( P01596679 ) ; Saint Philippe , Forêt de Mare Longue, April 1999, J.- Y. Dubuisson HR-1999-11 ( P) ; Saint Philippe , Forêt de Mare Longue, April 2002, J.- Y. Dubuisson HR-2002-15 ( P02433297 ) .

Note— Dubuisson et al. (2017) reported a clearly distinct lamina margin ( Fig. 7D ) that allows distinguishing the species from other Abrodictyum in the western Indian Ocean.

Genus Crepidomanes (C.Presl) C.Presl ( Presl 1849: 258)

Figures

FIGURE 7. Abrodictyum tamarisciforme (Jacq.) Ebihara & Dubuisson. A. A dense population of many individuals covering a trunk (La Réunion, ‘Grand Etang’). B. Single individual as epiphytic on a tree-fern trunk, which is also covered here by Didymoglossum cuspidatum (La Réunion, ‘Mare Longue’). C. Lithophytic individual, the little individual at the bottom right is A. parviflorum (Poir.) Bauret & Dubuisson (La Réunion, ‘Grand Etang’). D. Detail of segments with typical distinct marginal row of cells (mc) (photographs. A, C: J.-Y. Dubuisson; B: C. Chaussidon; D: L. Bauret).