## 3 Results and Discussion  
### Composition of Telekia speciosa Essential Oils  
After four hours of hydrodistillation, light-yellow EOs with a strong fragrant scent were isolated. The yields of EO from _T. speciosa_ leaves and flowers were 0.12% and 0.16% (\(w/w\)), respectively. Roots produced more volatile compounds (0.37%). EO yields from aerial parts and roots were modest and similar, as previously reported (leaf: 0.17%, flower: 0.19%, root: 0.41%) [10]. Over time, crystals were discovered in the root EO. This was most likely due to a high concentration of thymol derivatives. [PERSON] et al. discovered seven thymol derivatives in _T. speciosa_ oil, but two of them were not identified [6]. Nevertheless, in a prior work, we were able to identify these chemicals as 9-isobutyryloxythymol isobutyrate and 9-(2-methylbutyloxy)-thymol isobutyrate [10]. [PERSON] et al. studied the composition of EOs of _T. speciosa_ from Serbia and found the terpenoid fraction of the predominant group within the EO, with acyclic-farnesane sesquiterpenoids being the dominant compound class [5]. Scientific research covering the composition and biological properties of _T. speciosa_ EO has been going on for several decades as the plant colonizes new areas of Europe. The first wide and screened analysis based on the composition of EOs from Serbia was published in 2010 [5], while the EO composition from different parts of plants harvested in Poland was published in 2012 [10]. This article is a continuation of the research on \"Polish\" _T. speciosa_ oils, which, despite being an invasive plant in Poland, have benefits for honey bees. The knowledge based on the composition and biological properties of EOs from Bosnia and Herzegovina was expanded in 2021 [11]. It is worth mentioning that regardless of the region of origin of the _T. speciosa_ leaf EO, dominant volatiles are oxygenated derivatives of sesquiterpene, e.g., (E)-nerolidol (10%) and (_E,E_)-farnesol (6.7%). Both volatiles occurred in our previous results in reverse, but at simultaneously higher concentrations: (_E,E_)-farnesol (21.2%) and (_E_)-nerolidol (17.9%) [10]. Surprisingly, the composition of the flower EO differs strongly from our previous results [10]. The main flower volatiles are nerol (11.9%), linaill (6.9%), (Z)-nerolidol (6.1%), and \(\beta\)-carophyllene oxide (6.1%), which are opposite to the isoalantolactone and thymol derivatives, which were predominant in our previous study [10]. This may be due to genetic factors. The seeds of the plants studied in our previous study originated from west and southeast Europe, while the present study is focused on plants that grew from seeds collected in western Europe (France). Based on the previously and currently analyzed EO from _T. speciosa_ roots, we could conclude that the characteristic compound for the analyzed root oils is isoalantolactone, which constituted 62.3% and 46.2% of the oils, respectively. One of the major differences between this study and those previously reported [5,10,11] is the greater number of identified components. However, according to GC-FID-MS analysis, a few, still unidentified, significant compounds were detected in the examined oils. These volatiles were detected in quite high amounts in the leaf EO (2.8%) and flower EO (5.5%) of heartleaf oxeye. Among them, 5 compounds (numbers referring to Table 1: 111, 113, 115, 116, 117) exhibited very similar mass spectra, with molecular peaks [M]+ at \(m/z\) 206. Four of the five unidentified volatiles in this study were also found in our previous study [10]. The unidentified compounds have very similar fragmentation patterns and molar masses, as mentioned in the literature for macrophylilactone F. Due to the lack of a literature retention index for macrophylillactone, it has not been possible for us to confirm the structure of unidentified volatiles. The skeleton of macrophylilactone F is similar to isoalantolactone, the main volatile in EO root.