Didymoglossum lenormandii (Bosch) Ebihara & Dubuisson

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 : 18-19

Didymoglossum lenormandii (Bosch) Ebihara & Dubuisson

Didymoglossum lenormandii (Bosch) Ebihara & Dubuisson in Ebihara et al. , Blumea 51: 236 (2006). –

Trichomanes lenormandii Bosch, Nederlandsch Kruidkundig Archief 5 (3): 144 (1861), as ‘ lenormandi ’. – Type: ‘Hab. Ins. Mayotta pr. oras Africae australes’, L.H. Boivin s.n., Herb. de Limminghe (BR).

Trichomanes lenormandii Bosch var. angustilobum C.Chr. in Bonaparte , Notes ptéridologiques 9: 20 (1920a), as ‘ angustiloba ’. – Type: Madagascar, Massif de Manongarivo, H.Perrier de la Bâthie 7732 (holo-: P00466419!; iso-: P00466420!); Madagascar, Massif de Manongarivo, H.Perrier de la Bâthie 7738A p.p. (syn-: P00482639!).

Trichomanes lenormandii Bosch var. subcuspidatum C.Chr. in Bonaparte , Notes ptéridologiques 9: 21 (1920a). – Type: Madagascar, Grande Terre, H.Perrier de la Bâthie 7733 (holo-: P00466418!; iso-: P00466417!).

Short description

Lithophytic or epiphytic; long-creeping filiform rhizomes, rootless and densely covered by dense black trichomes, bearing widely separated pending fronds; fronds well stipitate, up to 6 cm long, linear to oblong, less often lanceolate to ovate, entire with undulate margins to pinnatifid, less often pinnate, with palmate to pinnate venation, and false veins parallel to true veins in addition to a submarginal false vein; numerous sori at the apex of lateral lobes, epitactic, cylindrical with a slightly dilated mouth.

Global distribution

Comoros, Madagascar, Tanzania.

Distribution in Comoros

Anjouan, Mayotte.

Additional specimens examined

COMOROS: ANJOUAN, Sommets élevés et boisés d’Anjouan, May 1850, L.H.Boivin s.n. (P01522381, only drawings). MAYOTTE, Qualey, Aug. 1849, L.H.Boivin 2883 (P00139633).

Note

The specimen P00466419 of Trichomanes lenormandii var. angustilobum , although not mentioned as the holotype in the original description, must be accepted as the holotype because the author of the name (Christensen) clearly used only this sheet (Art. 9.1, Note 1, McNeill et al. 2012) as stated by Bonaparte who mentioned on the sheet ‘Spécimens envoyés à M. Christensen. Retour avec sa lettre du 23 Août 1919’ and by the handwritten label by Christensen stating the specimen as a new variety. The same reasons explain the holotype specimen of T. lenormandii var. subcuspidatum . Futhermore, D. lenormandii is highly variable in terms of frond shape and division. Both varieties, angustilobum and subcuspidatum , illustrate such an infra-specific variability and are thus considered here as synonyms.

Didymoglossum lenormandii , with entire pinnatifid laminae, is smaller than D. kirkii with fronds up to 6 cm long. In addition, the number of sori exceptionally exceeds 6 per fertile frond in D. kirkii and each sorus is mostly located at the extremity of a long segment, while D. lenormandii exhibits usually 6 or much more sori per frond, which are born on short lateral lobes. Didymoglossum lenormandii can nevertheless be confused, especially the sterile fronds, with D. cuspidatum (unknown in the archipelago) because they often share the same gross lamina shape with undulated to lobed margins. But as for D. kirkii , sori of D. cuspidatum rarely exceed 6 per frond and they are apically located on ovate to obovate or deltoid fronds while they are mostly born on lateral lobes of oblong to lanceolate fronds in D. lenormandii .