2.5 Ancestral Area Reconstruction
To explore the biogeographic history of Notholirion plants, we
used three regions based on the paleogeographic and climatic evidence,
geographic distribution and floral composition throughout the
Himalayas-Hengduan Mountains (HHM) for ancestral area
reconstruction(Buerki et al., 2012; Tu, Volis, Dillon, Sun, & Wen,
2010; H. Y. Zheng et al., 2021):
(A) southern Himalayas, (B)
eastern Himalayas, (C) Hengduan Mountains. The Statistical
Dispersal-Vicariance (S-DIVA) analysis as implemented in the RASP v4(Y.
Yu, Blair, & He, 2020) was used for the reconstruction. We used the BI
tree based on the cpDNA datasets (obtained by phylogenetic analyses) for
the S-DIVA analyses. The uncertainty in the root areas of an outgroup
can lead to biased inferences for the crown node of the ingroups(Y. Yu,
Harris, Blair, & He, 2015), outgroups were removed before
ancestral-state reconstruction. To explore the effects of area
constraints, the maximum number of areas at each node was set to two.