FIGURE CAPTIONS
Fig. 1. Two approaches typically used to infer colonization times on oceanic island: stem and crown ages. Brown lines represent lineages with mainland distribution while green lines represent lineages with insular distribution. A. Graphical representation of stem and crown ages of a hypothetical island lineage (modified from GarcĂ­a-Verdugo et al. 2019a). B. Impact of assumed extinction or incomplete taxon sampling on the mainland when inferring island colonization times based on stem-age estimates. C. Impact of assumed extinction or incomplete taxon sampling on the archipelago when inferring island colonization times based on crown-age estimates.
Fig. 2. Classification of lineages according to divergence times for the Canarian thermophilous plant community, following the methodology proposed in this paper: (1) mediterranean lineages when stem and thus crown ages postdate the 2.8 Ma threshold; (2) pre-mediterranean lineages when crown and thus stem ages predate the 2.8 Ma threshold; and (3) undetermined lineages for those groups with stem ages before and crown ages after this temporal threshold. In these examples, 95%  intervals do not span the 2.8 Ma threshold, and therefore nodes can be unambiguously designated as mediterranean or pre-mediterranean.
Fig. 3. Assignment of mediterranean vs. pre-mediterranean nodes when the 95% HPD interval spans the 2.8 Ma threshold: (1) mediterranean nodes, when most of the posterior distribution of trees (> 50 %) provide node ages younger than 2.8 Ma, (2) pre-mediterranean nodes when most of the trees (> 50 %) provide node ages older than 2.8 Ma.
Fig. 4. The five thermophilous lineages of mediterranean origin (stem and therefore crown ages postdate 2.8 Ma) and related Canarian and mainland species from the 13 time-calibrated phylogenies inferred in this study using BEAST. Mean stem and crown ages and 95% posterior credibility intervals (blue bars and values in brackets) are indicated. Divergence times of the most recent common ancestor (marked as TMRCA) are also indicated for those groups in which stem and crown nodes showed low phylogenetic support (PP<0.90, BS<70). Circles at the nodes represent phylogenetic relationships with high posterior Bayesian probability (PP) and/or bootstrap (BS) support values (see legend). Color of plant names indicates vegetation type. Asterisks represent new samples included in the present study. The letters in the stem node or MRCA of the Canarian lineages represent the ancestral ranges inferred for that node by the Ancestral Area Reconstruction Analysis, and correspond to the following geographical areas: A: Mediterranean Basin, B: Macaronesia, C: Other regions (several letters imply ranges that include multiple areas).
Fig. 5. The three pre-mediterranean lineages (i.e. crown and thus stem ages predate 2.8 Ma) and related Canarian and mainland species from the 13 time-calibrated phylogenies inferred in this study using BEAST. Mean stem and crown ages and 95% posterior credibility intervals (blue bars and values in brackets) are indicated next to the corresponding nodes. The circles at the nodes represent phylogenetic relationships with high posterior Bayesian probability (PP) and/or bootstrap (BS) support values (see legend). Color of plant names indicates vegetation type. Asterisks represent new samples included in the present study.  The letters in the stem node of the Canarian lineages represent the ancestral ranges inferred for that node by the Ancestral Area Reconstruction Analysis, and correspond to the following geographical areas: A: Mediterranean Basin, B: Macaronesia, C: Other regions (several letters imply ranges that include multiple areas).
Fig. 6. The seven undetermined lineages (stem ages predating and crown ages postdating 2.8 Ma) and related Canarian and mainland species for the 13 time-calibrated phylogenies inferred in this study using BEAST. Mean stem and crown ages and 95% posterior credibility intervals (blue bars and values in brackets) are indicated next to the corresponding nodes. Divergence times of the most recent common ancestor (marked as TMRCA) are indicated for those groups in which stem and crown nodes showed low phylogenetic support (PP<0.90, BS<70). The circles at the nodes represent phylogenetic relationships with high posterior Bayesian probability (PP) and/or bootstrap (BS) support values (see legend). Color of plant names indicates vegetation type. Asterisks represent new samples included in the present study. The letters in the stem node or MRCA of the Canarian lineages represent the ancestral ranges inferred for that node by the Ancestral Area Reconstruction Analysis, and correspond to the following geographical areas: A: Mediterranean Basin, B: Macaronesia, C: Other regions (several letters imply ranges that include multiple areas).
Fig. 7. Stem ages of 43 Canarian lineages including thermophilous plant species. Results from the new phylogenies obtained in this study are indicated with plant names in bold (references in Table S1). Blue bars show the 95% intervals, and mean stem ages are marked by a black line.
Fig. 8. Twenty-eight crown ages of Canarian thermophilous plant lineages (i.e., including more than one sample from the Canaries) of the 43 shown in Fig. 7. Results from the new phylogenies obtained in this study are indicated with plant names in bold, while results from previously published time-calibrated phylogenies have non-bold plant names (references in Table S1). Blue bars show the 95% intervals, and mean crown ages are marked by a black line.