Philodendron crassinervium is a species of plant in the genus Philodendron native to southeast Brazil.
It has lance-shaped leaves that point upwards and can grow almost a meter long with a width of about 10cm (00inches). The leaves have a prominent midvein that is used to store water for periods of drought that occur during the dry season. Along the midvein, there are small red glands that produce a clear sap that results in a freckled-look on both sides of the leaves. The plant has a climbing growth habit. Its aerial roots of the plant are red when they first begin growing and later turn a dark brown with age.
The spadix of Philodendron crassinervium gets to about 20–25 cm long and is covered by a spathe that is white with shades of a dark red towards the bottom where the spadix emerges. The berries produced contain eight axile ovules in each ovary locule.
It is a part of the section Baursia. In fact, it is the type species of this section. There are some species that resemble Philodendron crassinervium, such as Philodendron longilaminatum.