## 4 Discussion  
The primary objective of this study was to better understand the assemblage of _Phellinus_ s.s. species present in North America using a multilocus dataset composed of isolates representing a broad geographic area. As hypothesized, at least eight species of _Phellinus_ s.s. occur in North America, yet the specific species assemblage was not accurately predicted. Up to this point, nearly all of the work aimed at elucidating the species in _Phellinus_ s.s. has been performed in Europe, albeit with some isolates originating from North America [4, 6, 7, 8, 9, 12, 40]. While some _Phellinus_ s.s. species have Holarctic distributions, the results of this study demonstrate clear differences in the North American assemblage that were not previously known. \begin{table}
\begin{tabular}{c c c c} \hline _Phellinus_ Species & **Known Range** & **Known Host Genera** & **Known Host Families** \\ \hline _P. alni_ & & _Acer_, _Almus_, _Betula_, _Carpinus_, & Betulaceae, Fagaceae, \\ _P. alni_ & Holarctic & _Coryilus_, _Fagus_, _Fraxinus_, & Juglandaceae, Oleaceae, \\  & & _Juglans_, _Laburnum_, _Malus_, & Rosaceae, Sapindaceae \\  & & _Padus_, _Prunus_ and _Sorbus_ & \& Ulmaceae \\ \hline _P. lundelli_ & Holarctic & _Betula_ & Betulaceae \\ _P. nigricans_ & Holarctic & _Betula_ & Betulaceae \\ _P. tremulae_ & Holarctic & _Populus_ & Salicaceae \\ _P. arctostaphyli_ & North America & _Arctostaphylos_ & Ericaceae \\ _P. bettulinus_ & North America & _Betula_ & Betulaceae \\ _P._ NA1 & North America & _Populus_ & Salicaceae \\ _P._ NA2 & North America & _Prunus_ & Rosaceae \\ _P. ignarius_ s.s. & Europe & _Populus_, _Salix_ and _Malus_ & Salicaceae and Rosaceae \\ _P. populicola_ & Europe \& Asia & _Populus_ & Salicaceae \\ _P. tuberculosus_ & Europe \& Asia & _Prunus_ & Rosaceae \\ _P. laevisatus_ s.s. & Europe \& West Asia & _Betula_ & Betulaceae \\ _P. orientcus_ & East Asia & _Betula_ & Betulaceae \\ \hline \end{tabular}
\end{table} 
Table 2: Known range, host genera and host families of _Phellinus_ s.s. species. In North America, _P. alni_ has the widest host range of any _Phellinus_ s.s. species, occurring on _Acer_, _Alnus_, _Betula_ and _Fagus_. Including its known host range in Europe, _P. alni_ inhabits at least 14 host genera, including _Frazimus_, _Juglans_, _Prunus_ and _Ulmus_[6, 12]. This broad host range is unique within the genus, as most members of _Phellinus_ s.s. exhibit a very narrow host range (see Table 2). Considering this, _P. alni_ is likely the most common species found in northern hardwood (_Acer-Betula-Fagus_), northern floodplain (_Frazimus-Populus-Ulmus_) and coastal _Alnus_ forests in North America. It is most likely widespread in _Quercus_-dominated forests as well, since many of the minor tree species in the _Quercus_ forest types are hosts for _P. alni_[41]. Phylogenetically, all four loci grouped _P. alni_ with _P. lundellii_, _P. igniarius_ s.s., _P._ NA1, _P. nigricans_ and _P. populicola_. Of this group, _P. igniarius_ s.s., _P._ NA1 and _P. populicola_ are known only from woody plants in the Salicaceae and Rosaceae. Interestingly, both [PERSON] [6] and [PERSON] _et al._[12] found that _P. alni_ does not infect members of the Salicaceae in Europe and this trend was observed in North America as well. Yet, _Populus_ was the only member of Salicaceae examined in this study and more targeted sampling of _Salix_ and _Populus_ species is necessary to conclude if _P. alni_ can attack these hosts. Additionally, this targeted sampling will help to conclude if _P. igniarius_ s.s. and _P. populicola_ are indeed present in North America. At present, these two species are known only from Europe and Asia. Attempts to utilize \"_Phellinus_\" specimens from the CFMR herbarium that were collected from _Salix_ proved these isolates belong to segregate genera such as _Fuscoporia_ (results not shown). Based on variations in morphological characters, [PERSON] [40] proposed that _P. laevis_ s.l. is composed of two species: _P. laevis_ s.s. from Europe and _P. betulinus_ from North America and Asia.