Crepidomanes minutum (Blume) K.Iwats.

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 : 21-22

9. Crepidomanes minutum (Blume) K.Iwats. ( Iwatsuki 1985: 524) var. minutum , Fig. 10C–E

Trichomanes minutum Blume (von Blume 1828: 223). ≡ Gonocormus minutus (Blume) Bosch (van den Bosch 1861a: 7–8, pl. 3). Type:— JAVA. Without locality, without date, C.L. Blume s.n. (lectotype L, L0544607!, specimen A, here designated). Note: also designated as type of T. parvulum Blume , non Poir. (1808).

= Trichomanes proliferum Blume (von Blume 1828: 224). ≡ Gonocormus prolifer (Blume) Prantl ( Prantl 1875: 51). Type:—JAVA. Without locality, without date, C.L. Blume s.n. (lectotype L, L0052391 !, here designated; isolectotype L, L0544607 !, specimen B).

= Trichomanes saxifragoides C.Presl. ( Presl 1843: 39). ≡ Gonocormus saxifragoides (C.Presl.) Bosch (van den Bosch 1861a: 9). Type:— PHILIPPINES. Luzon, without date, H. Cuming 256 (lectotype K, K000375720!, inadvertently designated by Tindale (1963); isolectotypes L, L0537118!, P, P00624459!).

= Trichomanes palmatum C.Presl. ( Presl 1843: 39, 40). Type :— PHILIPPINES. Luzon, without date, H. Cuming 209 (holotype L?; isotype P, P00624461 !).

= Trichomanes mannii Hook. ( Hooker & Baker 1868: 75, 76). ≡ Gonocormus mannii (Hook.) G.Kunkel ( Kunkel 1963: 212). ≡ Crepidomanes mannii (Hook.) J.P. Roux ( Roux 2000: 155). Type:— EQUATORIAL GUINEA. ‘Fernando Po’, before 1861, G. Mann s.n. (syntype K?; isosyntype GH, GH00022249!).

= Trichomanes lepervanchei Cordem. (Cordemoy 1891: 14). Type :— LA RÉUNION. Plaine des fougères, without date, M. Lepervanche-Mezière 7 (lectotype P, P 02141627!, here designated; isolectotype P, P 02141628!). Note. Cordemoy has not precisely designated the type among all the Lepervanche’s collected Hymenophyllaceae specimens. Such gathering (M. Lepervanche-Mezière 7) can nevertheless be a posteriori designated, as we did here, because it is the sole plant from the Lepervanche’s collection that can be attributed to the present species.

= Trichomanes matthewii Christ ( Christ 1909b: 56). ≡ Gonocormus matthewii (Christ) Ching ( Ching 1959: 177). Type:— CHINA. Kuangtoung: North river, Mong-si-hai, 11 December 1907, C.G. Matthew 26 (holotype P, P00623412!, isotype K, K001090162!). Note: in the introduction of his article including the description of T. matthewii, Christ (1909b) clearly mentioned that all the specimens are housed at the Muséum national d’Histoire naturelle, i.e. the Paris Herbarium (P). This allows treating the specimen at P as the holotype.

= Trichomanes musolense Brause ex Brause & Hieron. ( Brause & Hieronymus 1915: 377, 378). Type :— EQUATORIAL GUINEA. ‘ Westafrika : Fernando Poo , Musola oberhalb San Carlos (Westküste)’, November 1911, J. Mildbraed et al. 7057 (syntypes B, BW 20 0105426!, BW 20 0105427!; isosyntype P, P00482619 !).

= Trichomanes ruwenzoriense Taton ( Taton 1946: 31, pl. 3, figs K, L), as ‘ ruwenzoriensis ’. ≡ Gonocormus ruwenzoriensis (Taton) Pic. Serm. ( Pichi Sermolli 1968: 175). ≡ Crepidomanes ruwenzoriense (Taton) J.P. Roux ( Roux 2009: 40). Type:— DEMOCRATIC REPUBLIC OF CONGO. ‘Secteur des lacs Edouard et Kivu: Ruwenzori, Lamia’, before 1920, J.C.C. Bequaert s.n. (holotype BR, BR0000008054166!).

= Gonocormus australis Ching ( Ching 1959: 163). Type:— CHINA. Hainan, without date, E. Smith 1397 (holotype BM, BM001044300!).

Short description—Epiphytic or lithophytic; long-creeping filiform rhizomes, rootless and densely covered by dense black trichomes, bearing widely separated pending fronds; fronds with usually long terete wingless stipes ( Fig. 10D ) often bearing buds that can provide new fronds (called stipe proliferation; Fig. 10E ), up to 6 cm long, but more often less than 4 cm long, flabellate, palmatisect to digitate, less often pinnatifid, with sometimes, when dry, folds parallel to veins; sori few, paratactic, tubular to funnelform with a slightly dilated mouth; receptacle usually included to slightly exerted.

Global distribution—From central Africa to the Pacific islands (and Hawaï).

Current distribution in Mascarenes— La Réunion.

Ecology—Usually epiphytic in the Mascarenes (reported as mostly lithophytic in Asia) on tree-trunks in montane rainforests (950–1,600 m in western Indian Ocean, up to 2,000 m in Africa and Asia).

Specimen examined— LA RÉUNION. Without locality, 1892, H. J. de Cordemoy 133 ( P01627289 ) ; Bébour , May 2005, E. Grangaud 1679 (collector’s private collection) .

Note— Crepidomanes minutum var. minutum is usually observed as a rare epiphyte in montane rainforests, explaining its absence on Mauritius where such habitats are lacking, and specimens exhibit the typical stipe proliferation which is the synapomorphy of the section Gonocormus (Bosch) K.Iwats. ( Iwatsuki 1984: 174; see Ebihara et al. 2006) ( Fig. 10E ). As showed by Pynee et al. (2012) and Dubuisson et al. (2013) and as developed below, the lowland populations in the western Indian Ocean define a distinct variety characterized by smaller individuals and rarity of proliferation. In the western Indian Ocean, C. minutum var. minutum is considered as a dwarf species with laminae that rarely exceed 3 cm in length. But in continental Africa, ‘giant’ specimens with fronds that can exceed 6 cm (with bi-pinnatifid laminae up to 4–5 cm long) are not rare, especially at high elevations (up to 2,000 m), as illustrated by the specimens identified under the synonym C. ruwenzoriense (see Kornaś 1994).

Figures

FIGURE 10. A. Crepidomanes inopinatum (Pic.Serm.) J.P.Roux var. inopinatum, as lithophyte (La Réunion, ‘Petite Plaine’). B. C. inopinatum var. tamonii Y.Robert & Dubuisson, habit (Y. Robert 913, P02433924). C. C. minutum (Blume) K.Iwats. var. minutum, as epiphyte (La Réunion, ‘Bébour’). D. C. minutum var. minutum, frond with long terete wingless stipe. E. C. minutum var. minutum, showing stipe proliferation, scale = 1 cm (from Madagascar, F. Rakotondrainibe 3698, P00085267). F. C. minutum var. mascarenense Pynee & Dubuisson, as epiphyte (La Réunion, ‘Grand Etang’). G. C. minutum var. mascarenense, detail of fronds with short stipes. (photographs. A: J.-Y. Dubuisson; C–D: C. Chaussidon; F–G: E. Grangaud).