Thanks to Ruth for both today's photograph and write-up. I've tentatively identified the plant as Aristolochia grandiflora. Ruth writes:
If the stink doesn't kill you, the aristolochic acid will! Beware of the dutchman's pipe (Aristolochia)! Species of Aristolochia such as Aristolochia clematitis have been traditionally used in both western and Chinese medicine, with occasionally fatal outcomes. When it doesn't kill, it has also been known to cause nephropathy or liver disease.
The flowers of these particular plants smell of dead mouse in order to attract fly pollinators. My professor had one in class the other day and offered to let us smell it...it was dreadful! I couldn't get the rotten mousey stench out of my nose for hours.
The genus contains approx. 120 species of woody vines and perennials (ref: Mabberley's The Plant-Book). The floral architecture of aristolochias is obviously noteworthy. The flowers are inflated chambers formed by a fusion of the sepals. The corolla (ring of petals) is absent as the sepals are showy and ornate. The structure forming the pipe-like shape is called the tube and the tissues that fan out at the end to display the reproductive parts are called the limbs. The stamens and the style come together to make a gynostemium, with the ovary being inferior to the flower parts. For an illustration, and to see photographs of more species, see Aristolochias Native to Belize.
The name aristos means "best" and locheia means "childbirth", hence the families common name of the birthworts. In conclusion, study and admire this flower from a distance. Happy Halloween! BOO!