Polypodium acutum Burm. f.

Mazumdar, Jaideep, Callmander, Martin W. & Fumeaux, Nicolas, 2019, Typification and nomenclature of the ferns described in N. L. Burman’s Flora Indica, Candollea 74 (1), pp. 93-109 : 98

Polypodium acutum Burm. f. , Fl. Ind.: 232. 1768.

Lectotypus (designated here): SRI LANKA: sine loco, s.d., Hermann s.n. (BIF-CEYL p. 152, upper specimen) ( Fig. 3 ).

= Osmunda regalis L. , Sp. Pl.: 1065. 1753.

Notes. – No original material of Polypodium acutum has been located in G-PREL. BURMAN (1768) referred only to three pre-Linnaean polynomial names and an illustration (PLUKENET, 1694: tab. 285, fig. 1). One of these polynomial names referred to Burman’s father work: “ Burm. Zeyl. 98 ”. Johannes Burman’s Thesaurus zeylanicus, published in 1737, was based mainly on a Paul Hermann herbarium from Ceylon. This herbarium is bound in a folio volume now kept in BIF-CEYL with Benjamin Delessert’s personal library (see LOURTEIG, 1966). Page 152 of this bound herbarium features a collection of Polypodium acutum , bearing a reference to the protologue as well as the name of the new species, both from N.L. Burman’s hand. This collection, representing original material, is here designated as lectotype ( Fig. 3 ).

The lectotype matches with sterile pinnae of the fern Osmunda regalis , showing similar shape of pinnules and free venation. This species is widely cultivated and popularly known as ‘royal fern’. It does not occur naturally in Sri Lanka ( SLEDGE, 1981) and Hermann probably collected a cultivated plant.

Figures

Fig. 3. – Page 152 of Paul Hermann’s herbarium from Ceylon in BIF-CEYL with the lectotype of Polypodium acutum Burm. f. (upper specimen) and original material of Polypodium palustre Burm. f. (lower specimen). [© Bibliothèque de l’Institut de France, Paris]