L.H.Is.: top of Mt Gower, P.S.Green 1595 (A, K, NSW); SW corner of Mt Gower plateau, J.C.Game 69/020 (K, NSW); top of Mt Lidgbird, C.Moore 22 (K).
P.S.GreenRoyal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, England
Tree ferns with a definite trunk-like caudex. Stipe base usually ±persistent, eventually leaving a scar on the trunk; fronds small to large, 1–4-pinnate. Sori dorsal or marginal, round or ellipsoidal; indusia subtending and partially or entirely enclosing the sorus, or absent. Sporangia shortly stalked, often with paraphyses; annulus oblique.
A pantropical family of c. 8 genera and c. 700 species.
The genera Cystodium and Dicksonia are sometimes recognised as constituting a separate family, the Dicksoniaceae. R.Tryon (Contr. Gray Herb. 200: 1–53, 1970) proposed a reclassification of the Cyatheaceae not followed here. The following species were all treated in either Alsophila or Sphaeropteris.
G.Bentham, Filicales, Tribe Cyatheae, Fl. Austral. 7: 707–712 (1878); R.E.Holttum, The tree-ferns of the genus Cyathea in Australasia and the Pacific, Blumea 12: 241–274 (1964).
CyatheaSm. Mém. Acad. Roy. Sci. (Turin) 5: 416(1793) from the Greek kyatheion (a little cup), in allusion to the indusia in some of these ferns
Type: C. arborea (L.) Sm.
Tree ferns; apical bud clothed in scales. Fronds usually large, usually more than 1.5 m long, 1–3-pinnate or pinnatifid, with an indumentum of scales and hairs; stipe thick, densely covered with ±caducous scales towards the base; veins simple or branched, free. Sori dorsal on veins or vein dichotomies; indusia present or absent; receptacle erect, somewhat club-shaped to spherical; filamentous paraphyses often present.
A mainly tropical genus of c. 600 or more species, extending south to New Zealand, Chile and South Africa. Two species native to Norfolk Is.; 4 species native to Lord Howe Is.
1 Pinnules in the central portion of the pinnae 7–14 cm long, with 16–20 opposite pairs (before they diminish markedly in size towards the long, pointed apex)
2 Fertile pinnules deeply pinnatisect, the divisions in the centre of the pinnule joined basally along the costa by 0.5–1 mm of continuous lamina
3 Pinna rachis, costae and costules on the upper side at the base of the lamina with hairs and some scattered scales; stipe and primary rachis with a mixture of scales and crumpled hairs, but scarcely a felted indumentum (N.Is.)
3: Pinna rachis, costae and costules on the upper side at the base of lamina glabrous; stipe and primary rachis with felted indumentum of crumpled hairs (L.H.Is.)
2. C. macarthurii
2: Fertile pinnules completely pinnatifid, the divisions in the centre of the pinnules not joined by even a narrowly continuous lamina at their base
4 Lower surface of costae and costules scurfy with narrow setiferous scales, soon detached (L.H.Is.)
5. C. robusta
4: Lower surface of costae and costules ±felted with small, thin, entangled, fringed scales, soon detached (N.Is.)
6. C. brownii
1: Pinnules in central portion of pinnae 3–7 cm long, with 10–15 lamina segments (before diminishing in size towards the apex) (L.H.Is.)
5 Lower surface of costae and costules with small (0.15–1 mm long), scattered, 'bubble-like', bullate scales; pinnules deeply toothed, with acute teeth deflexed round sori
3. C. howeana
5: Lower surface of costae and costules without scales, somewhat prickly with the bases of early shed scales; pinnules ±entire except where fertile; fertile pinnules deeply toothed, with rounded teeth deflexed around sori
Trunk to 8 m tall; frond bases persistent; scars largish, shaggy. Fronds: stipe c. 50 cm long, prickly, scurfy-hairy; base covered with dark brown, twisted-pointed scales 2–4 cm long; costae and to a lesser extent costules covered below with a mixed tomentum of large pale scales, small 'bubble-like' scales and fine crumpled hairs (easily rubbed off); lamina bipinnatisect to tripinnate; primary pinnae to 50 cm long, ±flat, acuminate; secondary pinnae 8–10 cm long, c. 1.5 cm broad; largest pinnules 16–20 pairs, 8–10 mm long, 2.5–3 mm broad, with lowest 1 or 2 pairs of pinnules free, remainder adnate by a continuous lamina up to 1 mm wide on each side of costa. Sori without indusia.