What advantage to diversity are the position of the pistil and stamen?

the pistil or carpel is in the middle of the flower so that it id the first thing the insect gets to when pollinating


the stamens are at the side so that the bee rubs against them when reaching for the nectaries

What advantage to diversity are the position of the pistil and stamen?
You are asking about the relative positions of the stigma and the anthers ... this position is important in maximizing cross-pollination and thus maintaining genetic diversity. Plants do this in various ways. Here are a couple of examples:


1. At least some species of the Lipstick Plant (Gesneriaceae) have flowers with the anthers at the top of the tubular flower while they release their pollen (which is picked up on the heads of pollinators -- see pic at link), then the style moves up into the same position while the stamens drop down. Now the stigma is receptive to pollen on the heads of other pollinators that have visited flowers at the earlier stage. You can see the swap taking place in the top pic at the second link.


2. Distyly -- this is where a species has flowers of two different kinds, one with long styles and short stamens and another with short styles and long stamens. The thing is that the short style needs pollen from the short stamens and the long style needs pollen from the long stamens. There are some nice pics of the two kinds most of the way down the page at the 3rd link (yellow flowers).