Cyathea.~\ 
F1LICES. 
467 
Involucre thin, breaking up irregularly. C. borbonica, Desv.j Bojer , 
Hort. Maur. 388. C. robusta, Bojer j Wall. Cat. 182. Alsophila Tel- 
fairiana, Wall . ; Hook. Sp. Ml. i. 56. 
Mauritius, in the forests of Grandport and Savanne. Also Bourbon and Mada- 
gascar. C. Iwvigata, Willd. and C.Pervilleana and Commersoniana of Fee, are varieties 
with large pinnules, like the form figured in Hook. Sp. Fil. vol. i. t. 13 A. 
2. C. sechellaruna, Mett.j Hook, and Baker, Syn.Fil.22. Trunk 
reaching a height of 40-50 feet. Stipe 1-2 feet long, pale or dark 
brown, armed with small prickles, which extend to the rachises. 
Fronds 4-9 feet long, 2-4 feet broad, deltoid, tripinnate, dark green 
above, pale green or faintly glaucous beneath, minutely scaly on the 
midrib of the segments on the under side. Pinnae and pinnules both 
lanceolate, the latter 3-4 in. long, -J-f in. broad, cut down to the rachis 
into close lanceolate distinctly-toothed tertiary segments Va in. broad. 
Veins 1 0-1 2-ju gate, distinct, deeply forked. Sori crowded close to the 
midrib, confined to the lower half of the segments. Involucre a firm 
distinct hemispherical cup with an entire rim, like that of the American 
C. arbor ea. 
Seychelles, common in the hill-forests ofMahe. Endemic. 
3. C. excelsa, Swartz j Hook, and Baker , Syn. Fil. 22. Fronds 
tripinnate, reaching 6-8 feet long, moderately firm in texture, green 
and glabrous on both surfaces, with pale brown more or less prickly 
rachises. Pinnae and pinnules both lanceolate, the latter acuminate, 
3-4 in. long, |— 1 in. broad, cut down to the rachis into lanceolate dis- 
tinctly-toothed tertiary segments -§~J in. broad. Veins 10-15-jugate, 
deeply forked. Sori at the forking of the veins, forming a row close to 
the midrib. Involucre membranous, breaking up irregularly. C. 
arborea, Bory , Voy. i. 179, not Smith. 
Mauritius, in the forests of the Savanne and Black River ranges. Also Bourbon. 
C. glauca, Bory, which differs from C. excelsa by its tomentose rachises and glaucous 
under surface, is given by Bojer as Mauritian, but I have seen it from Bourbon only. 
5. DICKSONIA, Smith. 
Capsules stalked, splitting transversely, with an incomplete vertical 
ring. Sori globose, placed at the tip of a vein, either at or just within 
the margin. Involucre inferior, cup- or plate-shaped or furnished with 
two distinct lips. — Ferns of very various size and cutting, some ar- 
borescent, some dwarf with creeping rootstocks. Djstrib. Tropical 
and warm temperate regions of both hemispheres. Species 30-35. 
Frond simply pinnate. Involucre marginal, two-lipped 1. D. abrufta. 
Frond decompound. Involucre intra-marginal, plate- 
shaped 2. D. ANTHRISCIFOLIA. 
1. D. abrupta, Bory ; Hook and Baker , Syn. Fil. 32. Stipes 
short, tufted. Fronds lanceolate, simply pinnate, 2-3 feet long, 3-5 
2 h 2 
