The type species R. hickeyi is isolated to the Klondike Mountain Formation in the Ypresian Eocene Okanagan Highlands of northwest central Washington.

[1] 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.

[6] 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.

[7] The first Republica species to be named was initially studied and described by Harry MacGinitie in 1941 based on fossils from the Ione Formations Chalk Bluff and Buckeye Flat sites.

Based on a series of five cotypes, numbers 2199 - 2203 in the University of California Museum of Paleontology paleobotany collection, he named the new species Laurophyllum litseafolia.

However, he disagreed with MacGinities placement of the species in Lauraceae and opted to follow Edward W. Berrys choice of genus for similar leaves from the Wilcox Group.

Found at five sites in the Green River gorge area, Wolfe states that the two species form a gradual series, with the leaves having less than a 2:1 length/width ratio being placed in A. litseafolia and those with a length/width greater than 2:1 considered as A. kummerensis.

[6] During the study of fossil angiosperms from the Klondike Mountain Formation around Republic, Washington, Jack Wolfe and Wesley Wehr identified a leaf, specimen USNM 32697A, B. of unique venation and uncertain placement but bearing a similarity with both the species then included in Dicotylophyllum.

Likewise, they considered Gironniera, then placed in Ulmaceae, as superficially similar, but the numerous and well developed secondaries in Republica seem to exlcude a family relationship.

As such Wolfe and Wehr were still uncertain regarding the taxons higher affiliation and suggested placement into subclass Hamamelididae[1] of the now abandoned Cronquist system.

Molecular phylogenetics published by the Angiosperm Phylogeny Group broke up the subclass in the late 1990's,[8] with at least one pharmacognosist, Sonny Larsson, describing Hamamelididae as "grossly polyphyletic".

The thinner basal seconday pair both branch from the primary at an angle of around 50° before taking rather irregular paths towards the leaf margin, curving upwards and merging with tertiary veins below the next secondary apical.