Compared to the two Early Devonian euphyllophytes described
by Gerrienne et al. (2011) , Franhueberia is coeval
with the New Brunswick plant (late Emsian) and ≥ 6 million
years younger than the Châteaupanne plant (late Pragian–earliest
Emsian). The two plants reported by Gerrienne et al. and
Franhueberia are, thus far, the only records of secondary growth
in the Early Devonian. As the oldest examples of secondary
growth, they may hold the key to understanding the phylogeny
and evolution of the woody habit. In this context, it is important
to assess the taxonomic affi nities of Franhueberia .