Alsophila tussacii (Desv.) D. S. Conant

Cyathea tussacii Desv. Mem. Soc. Linn. Paris 6 : 323. 1827
Caudex 6-7 meters high, 10-15 cm. in diameter, rough, toward the crown very densely covered with sharp curved spines, the fronds deciduous (frequently all falling together seasonally), leaving large rough oval scars ; stipe very stout, 3 cm. or more thick at the base, 35-75 cm. long, curved, everywhere grayishfur f uraceous and densely armed with strong curved purplish-brown spines 6-9 mm. long, the inner side with numerous very narrow dark-brown scales ; lamina ample, 2.5 meters or less long, about 1.25 meters broad, slightly reduced at the base, tripinnate, coriaceous, dull-green above, gra3dsh-green beneath ; primary rachis yellowish-brown , tuberculate near the base, above muricate, finely furfuraceous, conspicuously fibrillose with slender striped tawny or grayish scales ; pinnae numerous, alternate or subopposite, approximate or their bases imbricate, sessile or short-stalked (only the lowermost long-stalked, up to 15 cm.), lanceolate, 60-70 cm. long, 18-24 cm. broad, slightly oblique, short-acuminate, the secondary rachis yellowish, furfuraceous, similarly fibrillose (especially at the base); pinnules about 35 pairs, approximate or slightly spaced, 8-11 cm. long, 1.7-2.3 cm. broad, at the base fully pinnate, nearly so throughout, tapering rather abruptly in the outer fourth to a serrate-acuminate apex, the costa pilose and densely paleaceous, the scales pale-olivaceous, lanceolate to ovate ; segments about 22-24 pairs, narrowly oblong, 9-11 mm. long, 3.5-4 mm. broad, close, slightly falcate, subacute, the margins entire, subrevolute, the costule clothed like the costa ; veins 11-13 pairs, mostly onceforked near the base ; sori 1-3 pairs, at the forking of the veins, close to the costule and obscuring it, basal on the segment; indusium deeply cyathiform, pale-brownish, membranous ; receptacle stout, setiferous, extruded with age.
Type locality : Jamaica.
Distribution : Known only from Jamaica, there common in damp forest ravines of the Blue mountains, at from 900 to above 1800 meters elevation.