Enigmatic Neviusia

Neviusia. The first time I heard it mentioned I was certain the conversation had switched from reality to the world of Harry Potter. I was wrong. The name belongs to a genus of plants that are totally real. What's more, the natural history of this small group is absolutely fascinating.

The genus Neviusia is comprised of two extant species. N. alabamensis is endemic to a small region of the southeastern United States around northwest Georgia and the Ozark Mountains. Its cousin, N. cliftonii, was discovered in 1992 and is endemic to a small area around "Lake" Shasta in California. Fewer than 20 populations have been found and of them, six were flooded to create "Lake" Shasta. It would seem very strange that both species in this genus are not only endemic to extremely localized regions but also completely disjunct from one another. This is only the beginning.

Whereas fruits have been described for N. cliftonii, none have been reported in N. alabamensis. Ever. Thanks to genetic analysis, populations of both plants are thought to be entirely clonal. High rates of pollen sterility are to blame. Why this is the case is hard to say. It is thought that the genus Neviusia is a relict of the early Cenozoic. Fossil evidence from British Columbia suggest that this genus was once more diverse and more wide spread, having gradually declined to its current limited distribution. The Pleistocene was likely the last straw for these plants, being corralled into small refugia of suitable habitat by the glaciers. Lack of seed production (perhaps due to genetic drift) meant that these two species were to never recolonize their former range. At least not without help...

Since their discovery, these two species have garnered some attention. Like Franklinia, Neviusia have become a sort of horticultural curiosity and have since been out-planted in a variety of locations. My first and only encounter with Neviusia occurred in a conservation garden. Despite their popularity among researchers and gardeners alike, it is unlikely that Neviusia will ever reclaim even a fraction of their former glory. Instead, they remain as endemic reminders of a bygone era. Despite their limited range I think it is important to remember just how long they have survived in North America. After millions of years of survival and persistence, their biggest threat is now us.

Photo Credit: Philip Bouchard (http://bit.ly/1WpElzX)

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