Phyllostegia warshaueri, of the Lamiaceae (mint) family, is a sprawling or climbing vine with end branches turning up, covered with upward-pointing fine, short hairs on the square stems that are 1 to 3 m (3.3 to 10 ft) long. The opposite, nearly hairless, toothed leaves are 9.5 to 20 cm (3.7 to 7.9 in) long and 2 to 6.6 cm (0.8 to 2.6 in) wide. Six to 14 flowers are borne in an unbranched inflorescence up to 20 cm (7.9 in) long with a main stalk 25 to 40 mm (1 to 1.6 in) long with conspicuous leaflike bracts. The green, hairless, cone-shaped calyx is 6 to 8 mm (0.2 to 0.3 in) long with triangular lobes. The corolla is white with a dark rose upper lip, sparsely hairy, and has a tube 18 to 20 mm (0.7 to 0.8 in) long; upper lip about 6 mm (0.2 in) long, and lower lip 12 to 15 mm (0.5 to 0.6) long. Fruits are divided into four nutlets 6 to 7 mm (0.2 to 0.3 in) long.