## 2 Results and Discussion
### Statistical Analysis of the Obtained Results
Therefore, samples belonging to group 1 located on the left (negative) side of the PCA diagram are characterized by a lower concentration (or lack) of the VOCs **40**, **48**, **60**, **63**, **66**, **71**, **79**, and **91**, as compared to group 2 located on the right (positive) side. In turn, samples from group 1 had a higher content of compounds **52**, **80**, and **106** than those from group 2. The separation of samples by genetic groups in PCA was confirmed by permutational multivariate analysis of variance (PERMANOVA, R\({}^{2}\) = 0.75, \(p\) < 0.001). Smaller differentiation within both groups (1 and 2) was observed along the PC2 axis, explaining 14.3% and predicting 9.9% of the total variation. This variation is related to geographical diversity and reflects the fact that the samples tested came from different geographical regions of Poland (Figure 4). On the PC2 axis, the highest positive (>0.70) factor loadings had VOCs **11**, **15**, **16**, and **74**, while compound **45** had negative factor loadings (Figure S4). Analysis of samples from different regions of Poland revealed small differences in the geographical distributions of the groups studied. Group 2 occurred mainly in the Pieniny and rarely in the Beskid Sadecki and Bieszczady Mountains (only one location), while group 1 had a wider distribution; it occurred in the Tatry, Male Pieniny, and Bieszczady Mountains, and less frequently in the Pieniny Mountains. It is worth emphasizing that at the site in the Lonny stream (in Pieniny), plants belonging to both groups grew together in one colony (samples CSU1-7 and CSU2-5) and had a composition of chemical compounds typical of the group (Tables S3 and S4). We did not observe visible differences between samples from a given region, nor between subsequent years of sample collection (Figure 5). The same result is shown by hierarchical cluster analysis (HCA). The dendrogram plotted on the basis of the Euclidean distance for all 107 compounds using [PERSON]'s method divided the studied samples into two clades that were consistent with their affiliation to the genetic groups. A large Euclidean distance between the two groups (>150) supports the significant difference in chemical composition between them. On the contrary, the Euclidean distances among samples in one group were about three times lower, suggesting that there are small variations between samples from a given group (1 or 2) that grow in different geographic regions (Figure 6). Similarly, the differentiation of the analyzed samples according to their genetic group was shown using a heatmap. The studied samples were separated into two main clusters correlated with their genetic classification, the first cluster including all 32 samples belonging to group 1, and the second containing 18 samples belonging to group 2. Heatmap analysis showed a high degree of correlation between the composition of VOCs in the analyzed samples of _C. suecia_ and the genetic group. The compounds formed three groups, the content of which in the tested plants clearly changed depending on their genetic affiliation (Figure 7). Slight differences related to region can be seen in group 2, especially between the Bieszczady sample and the remaining samples, which had a lower content of compounds **38**, **41**, **45**, **100**, and **104** and a higher content of **1**, **11**, **15**, **16**, **25**, **46**, **77**, and **105** (Figure S5). Figure 4: Two-dimensional PCA scatter plot based on all 107 detected compounds in the studied samples of _C. sucecia_ originating from different regions. The percentage of explained variance is 48.7% for PC1 and 14.3% for PC2. Different colors indicate the regions of origin. Figure 3: Two-dimensional PCA scatter plot based on all 107 detected compounds in the studied samples of _C. sucecia_. The percentage of explained variance (R2X) is 48.7% for PC1 and 14.3% for PC2, and predictive ability (Q2) is 44.0% and 9.9%, respectively. Different colors indicate genetic group affiliation. Shaded ellipses indicate the 95% confidence regions.