Amer. Fern J. 80: 15. 1990.
Petiole chestnut brown to dark brown, somewhat shiny, glabrous or sometimes viscid-glandular or rarely somewhat white-farinose proximally. Blade thin and herbaceous to thick and leathery, abaxially densely farinose, farina white or yellow, adaxially bright green to yellowish green when fresh, glabrous to glandular or viscid.
Habitat: Chaparral, pine and oak woodlands.
Elevation: 100–900 m
Pentagramma triangularis occurs in rock crevices and at the base of overhanging boulders in drainages and on slopes and roadbanks. Occasional plants in which the farina is nearly absent may be encountered. These have been described as Pityrogramma triangularis var. viridis Hoover, a name of uncertain application that appears to refer to misshapen-spored hybrids of various parentage within the Pentagramma triangularis complex.
|1||Leaves viscid-glandular adaxially; distal pinnae mostly entire; proximal basiscopic lobes of basal pinnae entire to undulate or crenate.||Pentagramma triangularis subsp. viscosa|
|1||Leaves glabrous or with scattered yellowish capitate glands adaxially, not viscid-glandular; distal pinnae mostly regularly lobed; proximal basiscopic lobes of basal pinnae pinnatifid, often deeply so.||> 2|
|2||Leaves with scattered yellowish, capitate, nonfarinose glands adaxially, white-farinose abaxially.||Pentagramma triangularis subsp. maxonii|
|2||Leaves glabrous adaxially, yellow- or white- farinose abaxially.||> 3|
|3||Farina light to bright yellow.||Pentagramma triangularis subsp. triangularis|
|3||Farina white.||Pentagramma triangularis subsp. semipallida|