Aristolochia littoralis (calico flower, elegant Dutchmans pipe) is a species of evergreen deciduous vine belonging to the Aristolochiaceae family.
Aristolochia littoralis is a climbing vine that can reach about 3–4.5 metres (9.8–14.8 ft) in length. The slender stems are woody and the leaves are bright green, cordate, amplexicaul, 7–9 centimetres (2.8–3.5 in) long and 5–10 centimetres (2.0–3.9 in) wide, forming a dense attractive foliage. Flowers are heart-shaped, greenish yellow with intricate purplish-brown markings. These unusual flowers are about 7–8 centimetres (2.8–3.1 in) long, grow solitary in the leaf axils and resemble a Sherlock Holmes pipe (hence the common name of "Dutchmans pipe"). The inner surface of the flared mouth is completely purplish-brown. The flowering period extends through all Summer. These plants are pollinated by flies which are attracted by the unpleasant carrion-like odor produced by the flowers. The numerous winged seeds are borne in dry dehiscent capsules that split like small parachutes. As the seeds are winged they are easily dispersed by wind. Plants in the related genus Pararistolochia differ by having fleshy moist fruit that do not split. This plant contains aristolochic acid, a toxic alkaloid. 
Images: Forest Starr & Kim Starr, CC-BY Creative Commons Attribution License 3.0