2.1 | Sampling
We selected one Qc population (eight in total) and one or twoQch populations (10 in total) in each of eight locations as well
as additional five Qc and one Qch populations around these
locations (Table 1). The eight locations were situated in mountain
ranges with alpine zones in northern and central Honshu (2, 4, 6, 7, 8,
9, 10, and 11 in Figure 2). We identified the taxon, Qc orQch , for each population based on growth habit, leaf size, and
hair density on the abaxial leaf surface according to Ohba (2006). Three
populations (05Hx, 06Hx, and 07Hx) were identified as Qch in the
field observation but were grouped to Qc in the following genetic
analysis (see Results 3.2). From each of the 24 populations, we sampled
leaves of 18–32 trees (693 individuals in total) along mountain trails
at intervals of at least 20 m in the summer in 2011–2012.
To measure leaf characters, we selected approximately three leaves from
each of 4–8 individuals in each of 12 out of the 24 populations (155
leaves of 53 individuals in total; Table 1). For genetic analysis, we
extracted DNA from leaves of all the 693 individuals in the 24
populations using DNeasy Plant Mini Kit (Qiagen, Hilden, Germany).