The unopened bud of a Pelican Flower, Aristolochia grandiflora ‘White’.
"Aristolochia grandiflora, named in 1788 by Olof Swartz (1760-1818), has one of the largest flowers of any New World species and deserves its name ‘grandiflora’ (large flower). Each trumpet-shaped flower lasts for two days. On the first day it is in the female phase, attracting flies by its foul smell, similar to that of rotting meat. The flies are trapped by the downward facing hairs in the pouch of the flower to ensure pollination. On the next day, the flower changes to male phase and pollen is deposited on the pollinators, the odour disappears, the hairs wither and the insects are released.” - Kew Conservation.
I grew this deciduous vine from seed in a large pot, training it to grow up a support post and railing of the outdoor deck off the back of our house.

Finalist - Monochrome