goldback fern

Like all ferns, P. triangularis does not produce flowers nor seeds, only spores. It has long smooth petioles (frond stems) that are anywhere from black to brown in color, and its fronds are bright to dark green on top with dark spore sacs (sporangia) on the leaf bottom surrounded by a lighter yellow excreted powdery substance. P. triangularis can grow to a height of 6 to 12 inches. In common with other Pentagramma species, the basal pinna has a characteristic asymmetry, with the basal secondary pinna on one side much (2 to 6-fold) longer than on the other. In response to dry conditions, the leaves curl up with the lower (spore) side outward, presumably to conserve water.

The distribution of P. triangularis includes much of the west coast of North America and extends from Vancouver Island, British Columbia, to Baja California, Mexico, east to Arizona, and in the Blue Mountains of south eastern Washington. This species is also found on the Pacific island of Guadalupe off the Baja California shore, and plants there may represent an undescribed taxon.

The fronds are eaten by species such as the Dusky-footed woodrat. The Indigenous tribes of California would use the goldback fern as an analgesic treatment. The Karuk tribe would use the fern to treat pain related to childbirth, and the Miwok tribe would use the fern as a treatment for toothaches. Additionally, Yurok tribe children would use the fern to create body art with the golden powder.