Pachycarpus vexillaris has complex or “busy” looking flowers in which the hairy, pointed and dark sepals around the perimeter and the broad, pale lilac (and sometimes faintly green) corolla lobes just inside them are easy to spot.
Inside the corolla there is a substantial corona with elaborately shaped lobes, found in flowers of the Apocynaceae family. The corona details differ much across the various Pachycarpus species, even more in other Apocynaceae flowers.
The flat style top is conspicuous in the flower centre. Some (other) Apocynaceae genera have two concentric coronas in their flowers, encircling the stamens and the style.
Insects have no difficulty in navigating among these complex floral innards for feeding themselves. In the process, they reciprocate for food received by carrying pollen, often enough of it to the right destinations. Otherwise they might lose their food resources.
People with books, cameras, hand lenses, brains, curiosity and perseverance can surely figure out the flowers as the insects do, although they don't require pollen. Such inquiries may range from fleeting acquaintance with the flowers to fair understanding and life-long or even intimate friendship and admiration. In this way surprises and depths of scientific discovery can be reached, with or without pollen on fingers and ticks in socks (Leistner, (Ed.), 2000; JSTOR; iNaturalist).