Classification
 Subordinate Taxa
 Nomenclature
Scientific Name:
Osmunda L., Sp. Pl. 1063 (1753)
Type Taxon:
Etymology:
Derivation unclear, but an old English name either for Osmund the ferryman, who saved the lives of his wife and daughter by hiding them amongst these ferns (Field 1890), or for Osmunder, the Anglo-Saxon god of thunder, equivalent to the Norse god Thor (Gledhill 2008), or King Osmund who reigned over the South Saxons about 785 AD (Burrows 1990 – see under Osmunda regalis).
 Description

Terrestrial ferns. Rhizomes erect, often forming a short woody trunk covered with persistent stipe bases. Rhizome scales absent. Fronds dimorphic. Stipes glabrous or woolly hairy. Laminae 2-pinnate, coriaceous, opaque, with stomata, deciduous, glabrous or hairy. Sporangia borne on highly modified and reduced laminal segments. Spores trilete, radially symmetrical, tuberculate with tubercles bearing slender echinate processes.

 Taxonomy

A genus of about 10 species. Phylogenetic analysis of DNA sequences from seven plastid loci by Metzgar et al. (2008) has shown that Osmundastrum is distinct from Osmunda, and that the latter comprises three separate subgenera. A single naturalised species is present in New Zealand (Brownsey in Webb et al. 1988; Brownsey & Smith-Dodsworth 2000), which is easily distinguished from the native species of Todea and Leptopteris by its markedly different fertile and sterile pinnae.

 Distribution

About 10 species, with one very widespread species, another in temperate North America and Eurasia, and the rest in east and south-east Asia. One species fully naturalised in New Zealand.

 Biostatus
Exotic
Number of species in New Zealand within Osmunda L.
CategoryNumber
Exotic: Fully Naturalised1
Total1
 Cytology

n = 22 (Kramer 1990).

 Bibliography
Brownsey, P.J.; Perrie, L.R. 2014: Osmundaceae. In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. Flora of New Zealand — Ferns and Lycophytes. Fascicle 4. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand ferns and allied plants. Edition 2. David Bateman, Auckland.
Burrows, J.E. 1990: Southern African ferns and fern allies. Fransden, Sandton, S.A.
Field, H.C. 1890: The ferns of New Zealand. A.D. Willis, Wanganui.
Gledhill, D. 2008: The Names of Plants. University Press, Cambridge.
Kramer, K.U. 1990: Osmundaceae. In: Kramer, K.U.; Green, P.S. Pteridophytes and gymnosperms. Vol. 1. In: Kubitzki, K. (ed.) The Families and Genera of Vascular Plants. Springer-Verlag, Berlin. 197–200.
Large, M.F.; Braggins, J.E. 1991: Spore atlas of New Zealand ferns and fern allies. SIR Publishing, Wellington.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.
Metzgar, J.S.; Skog, J.E.; Zimmer, E.A.; Pryer, K.M. 2008: The paraphyly of Osmunda is confirmed by phylogenetic analyses of seven plastid loci. Systematic Botany 33(1): 31–36.