Loadings of the environmental variables for each PC axis and tests of niche divergence and conservatism.

<p>* Significance level, <i>P</i><0.05. Bold values indicate niche divergence.</p><p>Observed differences in climatic niche for western and eastern lineages of <i>Nolina parviflora</i> on each PC compared to the middle 95th percentile of a null distribution of the differences between their environmental backgrounds.</p

Pairwise <i>F</i>_ST comparisons between pairs of <i>Nolina parviflora</i> populations in the TMVB. Populations located west of the TMVB are indicated by an asterisk (*). Site abbreviations are those used in Table 1. Significant values at <i>P</i><0.05 are in bold.

<p>Pairwise <i>F</i>_ST comparisons between pairs of <i>Nolina parviflora</i> populations in the TMVB. Populations located west of the TMVB are indicated by an asterisk (*). Site abbreviations are those used in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098754#pone-0098754-t001" target="_blank">Table 1</a>. Significant values at <i>P</i><0.05 are in bold.</p

Geographic location and population code for the 22 <i>Nolina parviflora</i> populations studied. Populations located west of the TMVB are indicated by an asterisk (*). TMVB = Trans-Mexican Volcanic Belt.

<p><i>n</i> the number of individuals per haplotype in parenthesis; <i>S</i> segregating sites; <i>h</i> haplotype diversity; π nucleotide diversity and SD. standard deviation.</p

Statistical parsimony network and map of geographical distribution of 11 cpDNA haplotypes found in <i>Nolina parviflora</i>.

<p>H1-H11: sampled haplotypes. Solid black circles: hypothetical haplotypes. Numbers in brackets indicate individuals. Pie charts represent chloroplast haplotypes for each sampling locality. Population numbers correspond to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098754#pone-0098754-t001" target="_blank">Table 1</a>.</p

Geographical distribution of <i>Nolina parviflora</i> along the Trans-Mexican Volcanic Belt.

<p>Population numbers are those given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098754#pone-0098754-t001" target="_blank">Table 1</a>. The bottom tree shows the results of the Bayesian molecular dating analysis of <i>N. parviflora</i>, numbers inside each clade indicate the populations included in the analysis, and node numbers indicate divergence time and its 95% highest posterior density (HPD) intervals (adapted from Ruiz-Sanchez & Specht, 2013).</p

Vegetative and floral morphological characters scored on specimens from the east and west clades of <i>N. parviflora</i> along of the Trans-Mexican Volcanic Belt.

<p>Vegetative and floral morphological characters scored on specimens from the east and west clades of <i>N. parviflora</i> along of the Trans-Mexican Volcanic Belt.</p

Potential distribution of <i>Nolina parviflora</i> identified using species distribution modelling (SDM).

<p>A  =  prediction of suitable habitat in the current environment. B  =  prediction projected onto the past climatic layers (LGM; CCSM), and C  =  prediction under past climatic conditions (LGM; MIROC). Blue colour indicates high probability of prediction of suitable habitat and red colour indicates areas with unsuitable habitat.</p

A-C west lineage.

<p>A. Plant showing two branches. B. Primary inflorescence branch, showing fruits and seed, scale bar  =  1 cm. C. Panoramic image of the oak forest type in the locality of Río Los Patitos, Zacatecas, Mexico. D-F east lineage. D. Plant showing seven branches and inflorescences. E. Primary inflorescence branch, showing fruits and seeds, scale bar  = 1 cm. F. Panoramic image of xerophytic scrub habitat type with Pico de Orizaba in the background, Veracruz, Mexico. Photos by E. Ruiz-Sanchez.</p

Heliconia alignment

Alignment of all Heliconia and outgroup Zingiberales species in the relaxed phylip format. See Heliconia partition file for partition boundaries. <br

Heliconia partition file

Partition file for Heliconia alignment file.<br