Sampling
In 2011–2015, we sampled 27 populations throughout the distribution
range of the seven Scutellaria species in Taiwan. Four of these
populations exhibited sympatry: two where both S. indica andS. barbata were present, one where both S.
austrotaiwanensis and S. taiwanensis were present, and one where
both S. playfairii and S. tashiroi were present (Fig. 1;
Table S1). Species identification of the collected samples was based on
Hsieh (2013), Hsieh and Huang (1995), Hsieh and Huang (1997), and Chao
et al. (2020). Fresh leaves from 4–46 individuals per population were
collected and dried in silica gel. The latitude, longitude, and altitude
of each sampling site were recorded (Table S1). A total of 504
individuals from 27 populations were sequenced in this study, making
this the most comprehensive sampling of Scutellaria on Taiwan
Island.