You often will find botanists and wildflower enthusiasts doing flips and cartwheels in the field when chance brings them to plants with petals of a pigment that differs from the norm for a given species. Okay, that's a bit of an exaggeration, but it is pretty exciting to find "forma" that are not as common as the typical species.
Last weekend, I led a field trip at Pine Station and Clark and Pine Nature Preserves in Northwest Indiana for Shirley Heinze Land Trust. A common species in the panne and swale communities is Liatris spicata, which normally has pinkish-purple flower heads clustered in a wand-like spike.
We were lucky enough to also see the white-flowered form of this species, Liatris spicata forma albiflora.
Also locally common in the drier sand at these sites is Liatris cylindracea, which normally has an open inflorescence of lavender-pink flower heads.
Lo and behold, we stumbled upon Liatris cylindracea forma bartelii, which has stark white disc flowers.
I never grow tired of seeing Liatris and the many insect species that visit them in their natural habitats, but it is even more of a thrill to see the white needle in the amethyst haystack once in a while.