Table 1. Analysis of molecular variance for Cronartium ribicola populations sampled across geographic regions, hosts and landscapes in North America.

Comparison a	Among groups (%)	Among samples within groups (%)	Φct b
Eastern vs western North America	23.3	5.1	0.233**
Coastal vs Interior Western North America	1.0	5.9	0.010**
Natural stands vs plantations c	1.2	4.4	0.012**
Host pine species c	0.0	4.2	0.000ns
Elevation c	0.0	4.3	-0.001ns

^aComparison among and within groups of populations arranged by geographic origin, type of stand, pine host and elevation.

^bProbability that the observed value is larger than the value calculated following permutation (**p<0.01). Φ_ct values were tested by permuting whole populations among groups.

^cSee S1 Table for details. Three pine species in western populations were considered: P. monticola, P. albicaulis, and P. flexilis . Other pine species (P. strobus, P. strobiformis) would have generated confounded effect of host and geography.