Nomenclature
Scientific Name:
Platycerium bifurcatum (Cav.) C.Chr., Index Filic. 496 (1906)
Synonymy:
  • Acrostichum bifurcatum Cav., Anales Hist. Nat. 1: 105 (1799)
Holotype: Port Jackson [Sydney, New South Wales], L. Née, MA 475361-1,2,3 (!online)
Etymology:
From the Latin bifurcatus (divided into equal limbs), a reference to the dichotomously branching lamina.
Vernacular Name(s):
elkhorn fern; elk's-horn fern; stag’s horn fern; staghorn fern
 Recognition

Platycerium bifurcatum is easily recognised by its perching, epiphytic habit and strongly dimorphic fronds, with sterile, appressed, orbicular to reniform, basal ‘nest’ fronds, and fertile, pendulous, dichotomously dividing, aerial fronds. The lamina segments are strap-shaped and densely covered in stellate hairs. The major veins divide dichotomously, but the minor veins are reticulate; the areoles lack free included veinlets, and hydathodes are absent. Sporangia form dense patches on the lamina between the apex and the first fork, paraphyses are present as stellate hairs, and indusia are lacking.

 Distribution

North Island: Northland, Auckland, Volcanic Plateau.

Known from Russell, Mt Maunganui and a few collections around Auckland.

Occurs naturally in Australia (Queensland, New South Wales) and Lord Howe Island (Bostock & Spokes 1998).

 Habitat

Recorded as a perching epiphyte on branches of Cordyline australis (cabbage tree), Metrosideros excelsa (pōhutukawa), and Eriobotrya japonica (loquat), and the trunk of Ficus macrophylla (Moreton Bay fig), in urban areas where it is likely to have spread from nearby cultivated plants.

 Biostatus
Exotic
 First Record

Heenan et al. (2004). Voucher: CHR 247069, 1971.

 Notes

Platycerium bifurcatum is treated here as a casual species, but it is becoming more common, particularly in Auckland, and further work is required to determine whether this is the result of deliberate planting, or whether the species is spreading naturally from cultivated plants.

 Bibliography
Bostock, P.D.; Spokes, T.M. 1998: Polypodiaceae. In: Flora of Australia. Vol. 48. 468–495.
Brownsey, P.B.; Parris, B.S.; Perrie, L.R. 2021: Polypodiaceae. In: Breitwieser, I. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 1. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Perrie, L.R. 2015: Polypodiaceae (excluding Notogrammitis). In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 1. Manaaki Whenua Press, Lincoln.
Cavanilles, A.J. 1799: Descripcion de los géneros Goodenia y Scaevola, del Arundo australis, y de diez especies del género Acrostichum. Anales de Historia Natural 1(2): 89–107.
Christensen, C. 1905–1906: Index Filicum. Hagerup, Copenhagen.
Heenan, P.B.; de Lange, P.J.; Cameron, E.K.; Ogle, C.C.; Champion, P.D. 2004: Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: additional records 2001–2003. New Zealand Journal of Botany 42: 797–814.
Steele, R.; Lowe, M. 2002–2006: Index. Subtropicals Index: 1–12.