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Cyatheaceae

Incl. Alsophilaceae

Terrestrial ferns, caudex massive, mostly erect, unbranched and tree-like, rarely appressed to trees and climbing, radial, dictyostelic with large gaps corresponding to leaf bases, vascular tissue surrounded by very hard sclerenchyma, growing apex protected by non-peltate, non-clathrate scales. Fronds long-stipitate, the stipe bases persistent of abscising at the trunk, vasculature of numerous small strands arranged in 3 arcs, pneumathodes present along each side of the stipe, lamina mostly bipinnate-tripinnatifid, sometimes tripinnate or simply pinnate, veins free to margin, mostly simple or forked; fertile fronds sometimes contracted. Sporangia borne on receptacle on the vein, the sorus exindusiate, or indusium completely covering sorus, or variously reduced to a mer scale or ring at the base of the receptacle, sori sometimes protected by overlapping scales, annulus +/- oblique, multiseptate paraphyses present; spores trilete, smooth or sculptured.

Distribution

A family of 2 (considered to be 6 by some authors) genera mainly in the warmer and wetter parts of the world, tropical and southern hemisphere, with at least 600 species. In Papuasia Cyathea is the only genus represented by c. 100 species.

Literature

Copeland, E.B. 1947. Cyathea in New Guinea. Philip. J. Sci. 77: 95 - 125.

Holttum, R.E. 1963. Cyatheaceae. Fl. Males. ser. 2, 1: 65 - 176. Addenda 562 - 563 1981).

Holttum, R.E. 1964. Tree ferns of the genus Cyathea in Australasia and the Pacific. Blumea 12: 241 - 274.

Holttum, R.E. 1982. Species of (Cyathea in the western Pacific related to C. multiflora Sm. And allies in America. Kew Bull. 37: 383 - 388.

Holttum, R.E. & Sen, U. 1961. Morphology and classification of tree ferns. Phytomorphology 11: 406 - 420.

Holttum, R.E. & Edwards, P.J. 1983. The tree ferns of Mt Roraima and neighbouring areas of the Guayana Highlands with comments on the family Cyatheaceae Kew Bull. 38: 155 - 188, pl. 7 - 9.

Tryon, R. 1970. The classification of the Cyatheaceae. Contrib. Gray Herb. 200: 3 - 53.

Genera

A single genus in Papuasia ... Cyathea (c. 100)

Note

Some authors, following Tryon 1970), prefer to subdivide the genus further; the Papuasian representatives can be separated with the following key:

Genera

1 Petiole scales structurally conform, the cells of the body similar in orientation, shape and usually in size and colour, mostly setiferous...

Sphaeropteris

Petiole scales structurally marginate, with a narrow to broad band of cells, different in orientation, size and usually in shape and colour from those of the central portion... Alsophila

It seems absurd to break up a morphologically rather uniform genus on the basis of the anatomy of the scales; for practical reasons it seems advisable to recognise a single genus and acknowledge the above differences at some infrageneric level.

The genera of the Dicksoniaceae in the wide sense (Dicksonia, Cystodium, Cibotium and Culcita) are sometimes included in this family, but on the basis of fundamental differences in indusial structure and hairy rhizome indument they are kept separate in this treatment.


Updated November 1999 by Jim Croft (jim.croft@environment.gov.au)