Crepidomanes minutum (Blume) K.Iwats. var. mascarenensis Pynee & Dubuisson, 2012

Pynee, Kersley, Hennequin, Sabine, Echternacht, Livia & Dubuisson, Jean-Yves, 2012, A new local variety of Crepidomanes minutum (Hymenophyllaceae) in the Mascarene Archipelago (Indian Ocean) and a new record for Mauritius, Phytotaxa 62 (1), pp. 25-30 : 28

Crepidomanes minutum (Blume) K.Iwats. var. mascarenensis Pynee & Dubuisson , var. nov. Fig. 2

Filmy ferns similar to the typical variety but the plants dwarfed and with exceptionally proliferating stipes.

Type :— MAURITIUS. Mt. Lagrave, 18 January 1974, D. Lorence s.n. (Holotype MAU! MAU-0009282)

Epiphytic ferns. Rhizomes creeping, branched, filiform, ca. 0.2 mm thick, densely covered with brown simple hairs, rootless or with root-like shoots covered with the same hairs as those on rhizomes. Fronds 0.2–5.0 cm apart; stipes 0.5–1.0 cm long, not winged, with brown hairs on its basal part, rarely observed as proliferous. Laminae light green on fresh materials to blackish green on dried materials, 0.5–1.5 × 0.5–1.0 cm, highly variable in shape, widely obovate to circular, lobed to mostly flabellate. Laminar segment linear, ca 0.5 mm wide, with true veins and sometimes longitudinal folds (in dried specimens) at each side of the true vein and simulating veins. Sori 1–3 per lateral segment, close to the apices; indusia immersed tubular to funnelliform, 1.6–1.8 × 0.8–1.2 mm, bordered on both sides by laminar cells, forming a large wing; mouth of indusia slightly dilated and not bilabiate, often broader than the segment; receptacles short to slightly exert.

Distribution and habitat in the Mascarenes:—Endemic to La Réunion and Mauritius, understory epiphyte on tree trunks in lowland rainforests (up to 1,400 m in La Réunion), often observed in Mauritius on Nuxia verticillata Lam. (Stilbaceae) trunks. Uncommon.

Worldwide distribution:—The complex of C. minutum is widely distributed in the Old World from Western Africa to the Pacific Islands (including Hawaii). The new variety is endemic to the Mascarene Islands of Mauritius and La Réunion.

Etymology:—The varietal epithet refers to the Mascarene Archipelago or Mascarenes.

Specimens examined (paratypes):— LA RÉUNION. Le Tremblet, 280–350 m, April 2003, J.- Y. Dubuisson HR-2003-5 ( P), J.- Y. Dubuisson HR-2003-6 ( P). Basse Vallée-Vallée heureuse, 860–960 m, May 2005, J.- Y. Dubuisson HR-2005-6 ( P). MAURITIUS. Osterlog Valley, 230–260 m, 20˚20’38’’ S, 57˚36’59’’ E, 6 October 2010, Hennequin et al. 340 ( P), Hennequin et al. 370 (MAU-0008233). Without locality, L. Barclay s.n. (MAU-0009281), as ‘ Hymenophyllum sibthorpioides ’

Figures

FIGURE 2. Crepidomanes minutum var. mascarenensis. A. In situ colony as epiphytic on a tree trunk (Mauritius, photograph by J.-Y. Dubuisson). B. Habitus, specimen J.-Y. Dubuisson HR2003-5 (P). C. Habitus, specimen J.-Y. Dubuisson HR2003-6 (P). S = sorus,