Republica is an enigmatic genus of flowering plants which includes three known species: Republica hickeyi, Republica kummerensis, and Republica litseafolia. The genus has been found in Eocene age geologic formations along the Pacific coast of North America. The affiliations of Republica are uncertain, with the most recent placement being tentatively in the now broken up subclass Hamamelididae.
Distribution The three species currently assigned to Republica are all known from western North America. The type species R. hickeyi is isolated to the Klondike Mountain Formation in the Ypresian Eocene Okanagan Highlands of northwest central Washington. The first named species, R. litseafolia has been identified from its type locality at the "Chalk bluffs" site in the northern area of California's Ione Formation. The site has been variously assigned to the early Eocene by Harry MacGinitie, based on attempted correlation to the Ione type strata resulting in a Ypresian age often being reported. However other authors suggest the age may be mistaken, based on anomalously low mean annual temperature estimates compared to other sites purported to be the same age located north and inland of the Chalk Bluffs site, with a possible 37 million years ago age begin suggested by Donald Prothero et al. (2011). Leaves assigned to R. litseafolia were later reported by Jack Wolfe (1968) from the Eocene Puget Group floras of the Green River gorge in King County, Washington by Jack Wolfe. Similar looking leaves were assigned to the third species R. kummerensis with the two separated by geochronology. R. litseafolia is most frequent in the older Franklinian and Fultonian stages before becoming scarce in the early Ravenian localities. R. kummerensis on the other hand first appears in the Puget groups late Ravenian and is found frequently in the Kummerian age sites. The R. kummerensis range was expanded by Wolfe (1977) to include the Kulthieth Formation (as the "Kushtaka formation"), in the panhandle of southeast Alaska. The formation was reported by Wolfe 1977 as early Oligocene and of the Kummerian paleofloral stage with R. kummerensis coming from two sites outcropping along the southern slopes of Carbon Mountain above Berg Lake, Hoonah–Angoon Census Area. The Kummerian has subsequently been revised to spanning between 40 mya and the Eocene-Oligocene boundary.
History and classification
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