Hypolepis parallelogramma is a species of fern native to the foothills of the Andes. Its fronds are 3 to 8 metres (10 to 30 ft) long, borne on brown stipes which grow paler in color towards the blade, armed with 0.6 millimetres (0.02 in) thorns. The rachis, like the top of the stipe, is light brown to straw-colored. The blades are oblong in shape and tripinnate, the pinnulets at the base being lobed (tripinnate-pinnatifid). Scattered tiny hairs are present on the underside (only) of the costae, costules, and some veins. Sori are at the edge of the leaf with straw-colored pseudoindusia. It most closely resembles H. melanochlaena, H. repens, and H. scandens, all of which are also large with thorny stems.