Classification
 Nomenclature
Scientific Name:
Cyathea smithii Hook.f., Bot. Antarct. Voy. II (Fl. Nov.-Zel.) Part II, 8, t. 72 (1854)
Synonymy:
  • Hemitelia smithii (Hook.f.) Hook. ex Hook. & Baker, Syn. Fil. 31 (1865)
  • Alsophila smithii (Hook.f.) R.M.Tryon, Contr. Gray Herb. 200: 37 (1970)
Lectotype (selected by Brownsey & Perrie 2015b): New Zealand, W. Colenso No. 770, K! (photo WELT E466/7).
  • = Hemitelia stellulata Colenso, Trans. & Proc. New Zealand Inst. 18: 222 (1886)
Lectotype (selected by Allan 1961): Norsewood, Herb. W. Colenso, 1884, WELT P003307!
  • = Hemitelia microphylla Colenso, Trans. & Proc. New Zealand Inst. 27: 399 (1895)
  • Hemitelia smithii var. microphylla (Colenso) Cheeseman, Man. New Zealand Fl. 951 (1906)
  • Cyathea novae-zelandiae Domin, Pteridophyta 264 (1929) nom. nov. pro Hemitelia microphylla Colenso 1895
Lectotype (selected by Brownsey & Perrie 2015b): Dannevirke, Herb. W. Colenso, WELT P002512!
Etymology:
Named in honour of John Smith (1798–1888), curator of the Royal Botanic Gardens, Kew.
Vernacular Name(s):
kātote; Smith's tree fern; soft tree fern
 Description
Rhizomes erect, forming a woody trunk up to c. 8 m tall, 120–320 mm in diameter, covered in dark brown appressed stipe bases; bearing scales near the apex. Rhizome scales marginate, acicular, lacking dark-coloured setae, dark brown, shining. Fronds 1650–3000 mm long, held horizontally; midribs of dead fronds persistent as a skirt around trunk. Stipes 80–450 mm long, 15–30 mm wide and 10–20 mm deep at the base, dark brown proximally, becoming chestnut or yellow-brown distally, weakly tuberculate and slightly rough, bearing hairs and scales; hairs fine, acicular, colourless or pale brown, up to 1 mm long; scales densely covering base of stipe, acicular, dark brown or chestnut-brown, shining, up to 60 mm long and 3 mm wide, becoming narrowly ovate, pale brown, and more scattered distally, interspersed with dense red acaroid scales c. 0.1 mm in diameter. Laminae 2-pinnate-pinnatisect to 3-pinnate-pinnatifid, ovate or elliptic or obovate, 1000–2000 mm long, 450–750 mm wide, dark green on adaxial surface, pale green on abaxial surface, herbaceous; adaxial surfaces of rachis and costae of primary pinnae abundantly covered in fine, acicular, colourless or pale brown hairs up to 1 mm long, becoming scattered on costae of secondary pinnae; abaxial surfaces bearing very scattered colourless acicular hairs, narrowly ovate or acicular pale brown scales lacking dark setae and up to 3 mm long and 0.5 mm wide, and colourless scales with ciliate margins or red acaroid scales c. 0.1 mm in diameter; rachis chestnut-brown, becoming yellow-brown distally. Primary pinnae in 20–30 pairs, narrowly ovate or narrowly triangular; the longest at or above the middle, 230–500 mm long, 60–130 mm wide, short-stalked, reducing proximally to a basal pair less than half the length of the longest pair. Secondary pinnae narrowly ovate or narrowly triangular, the longest 30–65 mm long, 7–16 mm wide, sessile. Longest tertiary pinnae 4–9 mm long, 1.5–2.5 mm wide, adnate or decurrent; apices acute; margins serrate or divided up to halfway to the costa. Sori 0.5–0.9 mm in diameter; paraphyses shorter than sporangia; indusia open on side away from costa before maturity, saucer-shaped at maturity and forming less than a hemisphere, not splitting with age.
 Recognition
Cyathea smithii is readily recognised in the field by its persistent dead stipes and rachises with abraded pinnae, which appear like a grass skirt around the trunk. The only other mainland New Zealand tree fern that regularly forms a skirt is Dicksonia fibrosa, where entire dead fronds are retained. Young immature plants of C. smithii are sometimes confused with C. colensoi, but fertile fronds are only produced on C. smithii when plants have developed trunks more than 1 m tall and can no longer be mistaken for C. colensoi.

Cyathea smithii can be distinguished from C. cunninghamii by its saucer-shaped, rather than hood-shaped indusia. The pale brown lamina scales are also distinctive in lacking dark setae at the apex (Brownsey 1979), and the acaroid scales never have an expanded pale brown base, as is sometimes the case in C. cunninghamii.

One collection of C. smithii from the Chatham Islands (WELT P021516) has larger pinnae than any mainland collection, with primary pinnae up to 600 mm long and 145 mm wide, secondary pinnae up to 80 mm long and 20 mm wide, and tertiary pinnae up to 14 mm long and 4 mm wide. It is unclear whether plants are generally bigger on the Chatham Islands.
 Distribution
North Island: Northland, Auckland, Volcanic Plateau, Gisborne, Taranaki, Southern North Island.
South Island: Western Nelson, Sounds-Nelson, Marlborough, Westland, Canterbury, Otago, Southland, Fiordland.
Chatham Islands, Stewart Island, Auckland Islands.

Altitudinal range: 0–1100 m.

Cyathea smithii occurs from near Kaitaia throughout the North Island, primarily in montane forest but extending locally into lowland areas. It ranges from 30 m in the Hunua Ranges up to 900 m in the Tararua Ranges, and 1100 m on Mt Taranaki. In the South Island, it occurs in lowland and montane forest, mostly west of the main divide, but also sporadically on the drier east coast. It extends from near sea-level to about 900 m on Avalanche Peak, Waimakariri, and 1100 m in north-west Nelson. It occurs also on the Chatham Islands, Stewart Island and on the Auckland Islands, the southernmost limit for tree ferns anywhere in the world.
 Habitat
Cyathea smithii is a hardy, subcanopy species which favours colder, wetter conditions, and is the dominant tree at higher altitudes and in the far south of the country. It occurs under podocarp, beech, kānuka and broadleaved forest.
 Biostatus
Indigenous (Endemic)
 Cytology
n = 69 (Brownlie 1958).
 Notes
There are six syntype specimens of Hemitelia stellulata Colenso in WELT (P002506-10, P003307), another at AK (143440), and two at K. Allan (1961, p. 43) lectotypified one of the specimens in WELT (P003307) by describing uniquely the material on the sheet (“a portion of a rachis with 8 pinnae”).

Buchanan (1887) recorded a specimen of C. smithii from Dunedin which branched to form several heads.
 Bibliography
Brownlie, G. 1958: Chromosome numbers in New Zealand ferns. Transactions of the Royal Society of New Zealand 85: 213–216.
Brownsey, P.J. 1979: Cyathea cunninghamii in New Zealand. New Zealand Journal of Botany 17: 97–107.
Brownsey, P.J.; Perrie, L.R. 2015: Cyatheaceae. In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. Flora of New Zealand — Ferns and Lycophytes. Fascicle 13. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Perrie, L.R. 2015: Taxonomic notes on the New Zealand flora: types in the fern families Cyatheaceae, Dicksoniaceae and Loxsomataceae. New Zealand Journal of Botany 53(2): 124–128.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand ferns and allied plants. Edition 2. David Bateman, Auckland.
Buchanan, J. 1887: On a remarkable branching specimen of Hemitelia smithii. Transactions and Proceedings of the New Zealand Institute 14: 356–357.
Cheeseman, T.F. 1906: Manual of the New Zealand Flora. Government Printer, Wellington.
Colenso, W. 1886 ("1885"): A description of some newly-discovered cryptogamic plants; being a further contribution towards the making known the botany of New Zealand. Transactions and Proceedings of the New Zealand Institute 18: 219–255.
Colenso, W. 1895: A description of two new ferns and one new Lycopodium, lately detected in our New Zealand forests. Transactions and Proceedings of the New Zealand Institute 27: 399–401.
de Lange, P.J.; Rolfe, J.R.; Barkla J.W.; Courtney, S.P.; Champion, P.D.; Perrie, L.R.; Beadel, S.N.; Ford, K.A.; Breitwieser, I.; Schönberger, I.; Hindmarsh-Walls, R.; Heenan, P.B.; Ladley, K. 2018: Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series No. 22. [Not Threatened]
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington. [Not Threatened]
Domin, K. 1929: Pteridophyta. Soustavný přehled žijících i vyhynulých kaprodorostů. Nákladem České Akademie, Prague.
Hooker, J.D. 1854–1855: The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror, in the years 1839–1843, under the command of Captain Sir James Clark Ross. II. Flora Novae-Zelandiae. Part II. Flowerless plants. Lovell Reeve, London.
Hooker, W.J.; Baker, J.G. 1865: Synopsis Filicum. Part 1. Hardwicke, London.
Tryon, R.M. 1970: The classification of the Cyatheaceae. Contributions from the Gray Herbarium of Harvard University 200: 4–53.
Webb, C.J.; Edgar, E. 1999: Spelling New Zealand in the specific and infraspecific epithets of vascular plants. New Zealand Journal of Botany 37(1): 71–77. [as Cyathea novae-zelandiae Domin]