Polyphlebium borbonicum (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 : 29

Polyphlebium borbonicum (Bosch) Ebihara & Dubuisson

Polyphlebium borbonicum (Bosch) Ebihara & Dubuisson in Ebihara et al. , Blumea 51: 240 (2006). –

Trichomanes borbonicum Bosch, Nederlandsch Kruidkundig Archief 5: 158, 159 (1861). – Type: ‘Hab. Ins. Borboniae’, L.H. Boivin 908 (lecto-: B200103881!, designated by Schelpe & Anthony (1986: 76); isolecto-: P00065006!).

Trichomanes goetzei Hieron., Botanische Jahrbücher 28: 339 (1900). – Type: Tanzania, W. Goetze 194 (holo-: B200093147!; iso-: BM).

Vandenboschia borbonica (Bosch) G.Kunkel , Nova Hedwigia 6: 213 (1963).

Crepidomanes borbonicum (Bosch) J.P.Roux, Conspectus of southern African pteridophyta: 45 (2001).

Short description

Epiphytic or lithophytic; long-creeping filiform rhizomes, bearing sparsely distributed roots and reddish brown trichomes, and widely separated pending fronds; fronds stipitate, up to 17 cm long, more often less than 10 cm long, deltoid to ovate, pinnate-pinnatifid to bipinnate-pinnatifid, without false veins or folds; sori numerous, paratactic, twice or more longer than wide, cylindrical with slightly dilated mouth.

Global distribution

Tropical Africa and the western Indian Ocean, or pantropical (see note).

Distribution in Comoros

Anjouan, Grande Comore.

Additional specimens examined

COMOROS: ANJOUAN, Sommet du Tringi, 12 Nov. 2009, M.Pignal et al. 3725 (P02439799). GRANDE COMORE, La Convalescence (versant ouest du Massif), 24 Nov. 2002, F.Rakotondrainibe et al. 6793 (P00312024); Versant ouest du volcan Karthala, bois proche de Convalescence, 24 Oct. 2008, M. Pignal et al. 3383 (P02439786).

Note

This species, firstly considered restricted to tropical Africa and the western Indian Ocean, would be included into a large complex associating species from the Pacific and Neotropics ( Ebihara et al. 2009). The species can be confused by its growth-form and gross frond shape and division with Crepidomanes bipunctatum and C. inopinatum . Both Crepidomanes species are rootless contrary to P. borbonicum but some Polyphlebium specimens can appear rootless if roots are not well developed. The sorus features are nevertheless more diagnostic. Sorus lips are clearly triangular in C. bipunctatum and not in P. borbonicum , and sori of P. borbonicum are twice or more longer than wide while sori of C. inopinatum are more or less as long as wide, always significantly less than twice longer (see Fig. 2C ).

Figures

Fig. 2. Illustration of representative descriptors and states used in the Xper database (see Appendix 1). A. Hymenophyllum hirsutum (L.) Sw., typical bilabiate sori (S) without a developed base, fully hairy lamina with pedunculated brown trichomes (see inset). B. Didymoglossum robinsonii (Hook. ex Baker) Copel., false veins (FV) parallel but not connected to true veins (TV) and marginal dark trichomes clustered here by 6 (see inset). C. Crepidomanes inopinatum (Pic. Serm.) J. P. Roux, typical trichomanoid sori (S) with a developed tubular base, lips are here dilated as a collar. D. Didymoglossum rotundifolium (Bonap.) J. P. Roux, false veins (FV) parallel but not connected to true veins (TV) and continuous submarginal false vein (smFV), here the one-cell thick lamina appears well translucent. E. Crepidomanes bipunctatum (Poir.) Copel., false veins more or less continuous and parallel to margins (mFV) and not connected to true veins (TV). F. Hymenophyllum sibthorpioides (Bory ex Willd.) Mett. ex Kuhn, bilabiate sori (S) with toothed margins. Photographs by A. H. Saïd.