Phacelia sewaneensis: New Flower Discovered in Shakerag Hollow

Annelise Matthiesen, Contributing Writer

Sewanee’s professor of biology Dr. Jon Evans has discovered a new plant species in Shakerag Hollow and has named it after the college it was founded in: Phacelia sewaneesis. The process for discovering this new flower led Evans through a journey of investigation and genetic research to rediscover a flower buried in time. 

Phacelia sewaneensis, the scientific name that  Evans has proposed for the new species, seems appropriate because Sewanee is a Native American name that translates to “lost.” and, as Dr. Evans puts it,  the flower was “lost since 1795, hiding in plain sight.”  Though not exclusive to Sewanee, it can be found in Shakerag Hollow every March: its purple and white blooms clinging to Sewanee sandstone.

A  small, critical observation prompted  Evans’ discovery of the “charismatic” new plant species. During his first year teaching at Sewanee, Evans observed that Phacelia bipinnatifida, a flowering plant with blue and purple variations, appeared in Shakerag Hollow in “patches,” or areas differentiated by a specific characteristic such as color.  

In the spring of 2021, Evans witnessed a tremendous spread of Phacelia bipinnatifida and observed additional differences. He determined that Phacelia bipinnatifida is a biennial, a type of plant living for two years, and its seeds can survive beneath the soil and germinate for up to five years. At the same time,  Evans said, he realized that purple and blue variations grew in different areas and had different stamen lengths, and spot patterns on the leaves. 

Evans said those differences prompted him to wonder: if Phacelia bipinnatifida’s pollen is transported between flowers by bees, carrying the same type of DNA, then why was the resulting patch of flowers so different with no evidence of intermixing?

Either the bees were not traveling between the blue and purple patches or the blue and purple flowers were simply not compatible for reproduction. Tests determined it was a lack of compatibility.

Working with post-baccalaureate research fellow JT Michel (C ‘24), Evans wondered if the blue and purple flowering plants might be individual species rather than forms of the same species.

Evans and Michel used iNaturalist, a website that enables users to view an archive for specific plant species, to locate other examples of Phacelia bipinnatifida growing wild in Georgia and Alabama. At these locations, they discovered the same pattern of differentiating patches of blue and purple flowers. 

Evans’ research partner, Furman University professor Dr. Ashley Morris, used genetic analysis to extract DNA from the samples and ascertain that the blue and purple varieties of Phacelia bipinnatifida are two different, reproductively incompatible species. 

Evans describes Morris’ genetic analysis as the “smoking gun” of the Phacelia research process. She notes that, when existing independently, “genetic and morphological data” can only “suggest” that Phacelia bipinnatifida is composed of two different species, but together, the two types of data produce convincing evidence for this conclusion. 

So how has a heavily-photographed North American species that’s been on the botanical radar since the 1790s managed to remain “hidden in plain sight,” as Evans puts it, for centuries? 

Evans acknowledges that an ecologist discovering a new species is “unusual.” However, he also acknowledges that his specialization has also afforded him a unique angle with which to approach his Phacelia research. As an ecologist, he said, he works to detect and understand patterns in the natural landscape that scientists who work primarily in an herbarium might easily overlook. 

The discovery raised a new challenge: what to name the flower, or rather, which flower to name.

If the team’s peer-reviewed research paper, Hidden in Plain Sight: A New Species of Phacelia for the Southern Appalachians, is accepted and successfully published, likely within the next month, then Evans will officially name the purple species of Phacelia. Michel, being the collector of the first samples, will have his name attributed to the first collected sample of the newly discovered species of Phacelia, “Phacelia bipinnatifida, up until now, was sitting in the National Museum of Natural History in Paris,”  Evans said, “A little tiny herbarium like we have here at Sewanee doesn’t get to have type specimens… until now.” 

In the coming months, especially once Phacelia blossoms,  Evans plans to give lectures on the discovery and may hold a contest to determine the new species’ common name. “This was one of those moments in science that most scientists don’t get,”  Evans said. “When you think of science, the average person thinks science is you work and work and then you have this eureka moment and then you’ve made your discovery and you publish it and that never happens, except, it did here.”