About Phlox glaberrima L.
Phlox glaberrima, commonly known as smooth phlox and sometimes called marsh phlox, is a flowering plant species belonging to the phlox family. It is native to the Midwestern and Southeastern United States, where it grows in moist to wet areas. It occurs in both prairies and forests, and acts as an indicator of high-quality natural habitat.
The evolutionary relationships between Phlox glaberrima, Phlox carolina, and Phlox maculata are particularly unclear. Hybridization between these species may occur, or there may be an undescribed third species that resembles an intermediate form between the known species. As of 2014, the phylogenetic relationships of this group of Phlox were still under review. Variations within the Phlox carolina–glaberrima complex are among the most difficult phlox plants to identify with certainty.
In 1955, botanist Edgar T. Wherry recognized three subspecies of Phlox glaberrima: subsp. glaberrima found across its eastern range, subsp. interior (called Wabash smooth phlox) from the Plains region, and subsp. triflora (synonym P. triflora, called three-flower smooth phlox) found in the South. However, in 2012 botanist Locklear only recognized two subspecies, merging subsp. triflora into subsp. glaberrima.
The glaberrima and interior forms, along with other taxa in the P. carolina–glaberrima complex and P. maculata, are frequently cultivated as ornamental landscape plants, while the triflora form is rarely cultivated. Notable cultivated cultivars of this species include Phlox glaberrima 'Morris Berd', Phlox glaberrima ssp. triflora 'Forever Pink', and Phlox glaberrima ssp. triflora 'Triple Play'.
