Sticherus revolutus (Kunth) Ching

Dicranopteris costaricensis Underw. Bull. Torrey
Club 34: 253. 1907.
Rhizome undescribed ; primary leaf-axis stoutish, rigidly erect, 3-4.5 cm. in diameter, continuous, the lower portion brownish-castaneous, glabrous and shining, the upper portions light-brownish and thickly clothed with deciduous spreading deltoid -lanceolate attenuate long-ciliate yellowish scales ; lateral branches 1 or 2 pairs, spreading, normally three times pseudodichotomous (secondary and tertiary axes invariably wanting), the divisions widely divaricate ; primary internodes 4-9 cm. long, arcuate, 2.5 mm. in diameter, with several crowded stipuliform segments at the base, otherwise naked, deciduously paleaceous ; secondary internodes widely divergent, 3.5-6.5 cm. long, sometimes naked, more commonly pectinate (at least in the lower half), stipulate; tertiary internodes 3-5 cm. long, fully pectinate, these and the pinnae densely paleaceous below, the scales similar in form to those of the upper primary leaf -axis, but brightferruginous, persistent, wide-spreading ; pinnae linear, 10-30 cm. long, 1.25-2.7 cm. broad, attenuate, cut to the rachis ; segments close, thick and rigidly coriaceous, dull dark-green above, subglaucous below, 7-14 mm. long, 4-6 mm. broad at the base, oblong to deltoid -oblong, obtuse (often appearing deltoid and acute in drying), the margins entire and widely revolute, the costae elevated and deciduously paleaceous ; veins 8-11 pairs, evident below, mostly once-forked above the base, together with leaf-tissue obscurely setulose ; sori normally 5-sporangiate, medial or slightly supramedial, apart from the costa, seated on the anterior branch.
Type locality : Volcan de Poas, Costa Rica, altitude 2600 meters.
Distribution : Apparently confined to the upper slopes and summits of the high peaks of Costa Rica (volcanoes of Poas, Turrialba, Barba, and Irazli), altitude 2400-3000 meters.