Cyathea laevigata Willd. ex Kaulf.

Janssen, Thomas & Rakotondrainibe, France, 2006, A revision of the fern family Cyatheaceae in the Mascarene Islands, Adansonia (3) 28 (2), pp. 213-241 : 237-238

Cyathea laevigata Willd. ex Kaulf.

Enumeratio Filicum 256 (1824). — Schizocaena laevigata (Willd. ex Kaulf.) J.Sm. , Journal of Botany (Hooker) 1: 661 (1842). — Cyathea canaliculata Willd. ex Spreng.var. laevigata Mett. ex Kuhn, Filices Africanae 163 (1868). — Cyathea borbonica Desv. var. laevigata (Willd. ex Kaulf.) Bonap. , Notes ptéridologiques 9: 49 (1920); Christensen, Dansk botanisk arkiv 7: 21, pl. 4, f. 18-19 (1932), excl. specim. madag.; Tardieu in Humbert, Flore de Madagascar et des Comores, fam. 4: 14, f. 1, 6-7 (1951), excl. specim. madag. — Type: “Habitat in Madagascaria”, A. du Petit- Thouars s.n. (holo-, B-W! no. 20181; putative iso-, P!).

REMARKS

The holotype in B-W! consists of a single pinna with a rachis fragment and oblong, sessile pinnules, 3 × 0.6 cm, subcordate at their base and with crenate apices. Except for scattered acaroid squamules on the abaxial face and rare narrowly lanceolate crispate scales on the adaxial face, rachis and costa do not carry any conspicuous indument. The sori are very young, distant from each other and subcostular on the first bifurcation of the 1- 2-furcate veins. The lamina is glabrous on both surfaces. Du Petit-Thouars s.n. (P!) from Madagascar consists of a leaf apex and a rachis fragment with four pinnae. It is morphologically identical to the holotype and considered to represent a putative isotype .

Both specimens are morphologically very close to Cyathea canaliculata var. latifolia Hook. from Mauritius and to some forms of Cyathea borbonica var. borbonica from Réunion, but do not correspond to any known material from Madagascar. The leaf base with scales being unavailable in the original material, it is impossible to unambiguously assign the plant to either of these species or to a currently unrecognized Madagascan taxon. Du Petit-Thouars has been collecting in Madagascar ( Dorr 1997) as well as on both of the Mascarene Islands and we can therefore not exclude that the type of the name is indeed from Madagascar. If it can be proven that the specimen has been collected on Mauritius or if more isotypes can be found to complement the current description of Cyathea laevigata , ascertaining its identity with a Mauritian taxon, an epitype should be chosen and necessary rearrangements in synonymy made. As both conditions are currently not fulfilled, we are unable to clarify the status of Cyathea laevigata Willd. ex Kaulf. in the present treatment.

The epithet laevigata , based on the type in Willdenow’s herbarium, has been combined under Cyathea borbonica Desv. by Bonaparte (1920: 49; pro varietate). It has been applied by this author, Christensen (1932) and Tardieu-Blot (1951) to a Madagascan tree fern with adnate pinnules that is most likely only distantly related to the Mascarene taxa (Janssen & Rakotondrainibe unpubl.).