Subordinate Taxa
Scientific Name:
Arachniodes Blume, Enum. Pl. Javae 2, 241 (1828)
  • = Polystichopsis (J.Sm.) Holttum, J. Linn. Soc., Bot. 53: 149 (1947)
  • = Byrsopteris C.V.Morton, Amer. Fern J. 50: 149 (1960)
Type Taxon:
Arachniodes aspidioides Blume
From the Greek arachniodes (like a spider’s web), a reference to the indumentum of one species.

Terrestrial ferns, evergreen. Rhizomes long-creeping, scaly. Rhizome scales non-clathrate, narrowly ovate to narrowly triangular, margins entire or toothed, attached at base, concolorous, pale brown or red-brown. Fronds monomorphic, not bulbiferous. Stipes and rachises scaly, adaxially sulcate. Laminae 3–4-pinnate (NZ), rarely 1–2- or 5-pinnnate (not NZ), coriaceous (NZ) or herbaceous (not NZ), scaly. Veins free. Sori round, borne on abaxial surface, away from the margin, in 1 row either side of midrib; indusia reniform, peltate. Spores monolete; perispores rugose or tuberculate, often minutely echinate on the surface.


A genus of over 80 species, included in the subfamily Dryopteridoideae (Lu et al. 2019).

Arachniodes is sister to Dryopteris, with these two genera in turn sister to the polystichoid ferns (Liu et al. 2016Lu et al. 2019).

Only one species, Arachniodes aristata, occurs in New Zealand, where it is confined to the Kermadec Islands. It was treated as Rumohra aristata by Allan (1961).


In New Zealand the sole species of Arachniodes is confined to the Kermadec Islands. It is recognised by its terrestrial habit, long-creeping rhizomes, 3–4-pinnate laminae, scaly fronds, and round sori protected by reniform indusia. The spores are rugose with minute papillae on the surface (Large & Braggins 1991).


Arachniodes is a genus of tropical and temperate regions. The greatest diversity is in China and the Himalayas, with a few species extending to Africa, tropical America, Australia and the Pacific (Tindale 1961); 40 species in China (He et al. 2013), two in Africa and Madagascar (Roux 2009), and one widespread species in Australia and the Pacific (Jones 1998; Nakamura 2008). One non-endemic species in New Zealand.

Indigenous (Non-endemic)
Number of species in New Zealand within Arachniodes Blume
Indigenous (Non-endemic)1

The base chromosome number in Arachniodes is x = 41 (Kramer 1990).

Blume, C.L. 1828: Enumeratio Plantarum Javae. J.W. van Leeuwen, Leiden.
Brownsey, P.J.; Perrie, L.R. 2021: Dryopteridaceae. In: Breitwieser, I. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 31. Manaaki Whenua Press, Lincoln.
He, H.; Wu, S.; Xiang, J.; Barrington, D.S. 2013: Arachniodes. In: Zhengyi, W.; Raven, P.H.; Deyuan, H. (ed.) Flora of China. Lycopodiaceae through Polypodiaceae. Vol. 2–3. Science Press, Beijing.
Holttum, R.E. 1947: A revised classification of Leptosporangiate ferns. Journal of the Linnean Society. Botany 53: 123–158.
Jones, D.L. 1998: Dryopteridaceae. In: Flora of Australia. Vol. 48. 393–418.
Kramer, K.U. 1990: Dryopteridaceae. 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.
Kramer, K.U.; Green, P.S. 1990: Pteridophytes and gymnosperms. Kubitzki, K. (ed.) The Families and Genera of Vascular Plants. Vol. 1. Springer-Verlag, Berlin.
Large, M.F.; Braggins, J.E. 1991: Spore atlas of New Zealand ferns and fern allies. SIR Publishing, Wellington.
Liu, H.-M.; Zhang, X.-C.; Wang, M.-P.; Shang, H.; Zhou, S.-L.; Yan, Y.-H.; Wei, X.-P.; Xu, W.-B.; Schneider, H. 2016: Phylogenetic placement of the enigmatic fern genus Trichoneuron informs on the infra-familial relationships of Dryopteridaceae. Plant Systematics and Evolution 302: 319–322.
Lu, N.T.; Ebihara, A.; He, H.; Zhang, L.; Zhou, X-M.; Knapp, R.; Kamau, P.; Lorence, D.; Gao, X-F.; Zhang, L-B. 2019: A plastid phylogeny of the fern genus Arachniodes (Dryopteridaceae). Molecular Phylogenetics and Evolution 133: 214–235.
Morton, C.V. 1960: Observations on cultivated ferns. VI. The ferns currently known as Rumohra. American Fern Journal 50: 145–155.
Nakamura, M. (ed.) 2008: Illustrated flora of ferns and fern allies of South Pacific Islands. National Museum of Nature and Science Book Series No. 8. Tokai University Press, Tokyo.
Roux, J.P. 2009: Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23: 1–296.
Tindale, M.D. 1961: Aspidiaceae. Contributions from the New South Wales Herbarium, Flora Series 211: 47–78.