Viewing the pendulous flowers of Hermannia joubertiana from below, shows the spiral petal twist characteristic in Hermannia. The small flower mouth looks dark amidst the five golden-yellow petals in the photo.
The petal arrangement leaves only a tiny entrance for pollinators, allowing them access on a selective basis. In nature body size or shape of feeding organs may serve as barriers to entry, like theatre or sports stadium tickets… if you can’t reach, you don’t share.
Functional sculpting of specialised organic shapes, a slow and meticulous co-evolution of moth or butterfly proboscis aligned with gradual flower structure development, result in some of the specific form combinations found among nature’s miraculous feeding-cum-pollination solutions (Privett and Lutzeyer, 2010; JSTOR).