Hemiepiphytic; stem scandent; internodes very long andslender, 20 cm long, less than 3 mm diam.; roots drying dark brown; cataphylls unknown, probably <10 cm long, lanceolate, deciduous; LEAVES: petioles 7--7.4 cm long, 1 mm diam., obtusely flattened abaxially; blades narrowly ovate, very long-acuminate at apex (the acumen 2.4--2.6 cm long), subcordate at base, 11--11.6 cm long, 5--5.5 cm wide (ca. 2 times longer than wide), (ca. 1.5 times longer than petiole), about equal in length to petiole, drying brown; posterior lobes rounded to obtuse, 2--3 mm long, 1.4--1.7 cm wide; sinus arcuate with blade decurrent on petiole, 2--3 mm deep; midrib drying with up to 5 ribs above; basal veins 2--3 per side, with all free to base, obscure; primary lateral veins 2 per side, departing midrib at a 40--45º angle, straight to the margins; minor veins arising from the midrib only. INFLORESCENCES nearly as long as leaves, probably 1 per axil; peduncle 6 cm long, 4 mm diam., 0.83 times the petiole length; spathe 7.4 cm long, (1.2 times longer than peduncle), green to reddish within, spadix pinkish throughout (fide field notes, in part lost); pistils 2.2 mm long, 1.1--1.2 mm diam.; ovary (3)5--6(8) locular, with axile placentation; ovules 8--12 per locule, mostly 1-seriate, 0.1--0.2 mm long, slightly longer than funicle; funicle ca. 0.1 mm long, adnate to lower part of partition, style similar to style type B; style apex domed; the androecium truncate, oblong, prismatic, margins irregularly 4--5-sided, 0.7--1 mm long; thecae oblong, 0.3 mm wide, more or less parallel to one another; sterile staminate flowers irregularly 4--5-sided, 0.8--1.2 mm wide.
The species is characterized by its scandent habit, very long and slender internodes (drying <3 mm diam.), slender petioles about as long as the small, narrowly ovate, subcordate blades, and especially by the inflorescence being longer than the petioles. Philodendron chirripoense is not similar to any other species in either Central or South America, but it might be confused with P. microstictum, the only other species that has the inflorescence longer than the leaves. The latter has larger blades (more than 13 cm wide) which are often broader than long.