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Dicksonia L'Herit.

Terrestrial, large, arborescent. Rhizome an erect stout caudex bearing a radial tuft of fronds at its apex, dictyostelic, supported by strong bands of sclerenchyma, young parts and bases of stipes densely covered with long, fine, and/or coarse hairs. Fronds short- to moderately long-stipitate, the base of the stipe with 3 arcuate, continuous or interrupted vascular strands concave internally, the 2 adaxial strands within the abaxial strand, all 3 uniting upwards to form a single +/- "U"-shaped vascular strand, rachises adaxially raised but not continuous with each other, the lamina tripinnate or deeply tripinnatifid, the basal pinnae narrowed, the pinnules deeply lobed and dimorphic, the fertile pinnules contracted and more deeply lobed than the sterile; veins in the ultimate segments pinnately arranged about a prominent costule, free, simple, forked or +/- pinnate in each tooth or lobe. Sori submarginal, terminal on simple veins or on the basal acroscopic branch of a branched vein, the receptacle raised and elongate along the vein end, protected by a reflexed lobe of the lamina (outer or false insudium) and an inner, saccate indusium attached to the basiscopic side of the receptacle; sporangia maturing basipetally, stalked, annulus complete and oblique, stomium lateral; paraphyses, numerous, simple, multiseptate, with a red-brown terminal cell. Spores trilete, smooth to sculptured.

Species in Papuasia

1a. Base of stipe clothed with dark red spreading hairs 30-50 mm long; hair of the undercoat pale, slender or flaccid, much shorter 2
Base of stipe clothed mainly with soft, matted, red-brown hairs, with or without a smaller number of stout, rigid, dark red hairs 3
2a. Some hairs on costae flaccid, some spreading, mostly pale D. sciurus
Hairs on costae ascending, mostly dark red D. archboldii
3a. Some stout, rigid, spreading, dark red hairs present near the base of the stipe, and scattered also on the pinna-rachis, the pinna-rachis mainly clothed with a close layer of matted, flaccid hairs D. hieronymii
No stout, rigid, spreading, dark red hairs mixed with softer hairs on the stipe bases 4
4a. Pinna-rachis rather dark and +/- glabresent; costae bearing flaccid pale hairs +/- mixed with thick dark hairs with pale bases D. grandis
Pinna-rachis brown, persistently hairy beneath; costae bearing entirely pale flaccid hairs D. lanigera