## 2 Results and Discussion
### Chemical Composition of Headspace Samples from C. dactylon, C. exaltatus, and P. repens
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**S**} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{3}{c}{**Relative Composition \% [Peak Area/Total Area] \(\pm\) Standard Error**} \\ \cline{3-10}  & & & & \multicolumn{3}{c}{_C. dactylolololumn{1}{c}} & \multicolumn{3}{c}{_C. csaltatus_} & \multicolumn{1}{c}{_P. repens_} \\ \hline
**No.** & **Compound** & **RT** & **RI** & **Class** & **Root** & **Shoot** & **Root** & **Shoot** & **Root** & **Shoot** \\ \hline
24 & cycpenene & 14.22 & 1422 & TR & - & - & \(10.34\pm 0.93\) & \(4.72\pm 0.33\) & - & - \\
25 & cy-cpenene & 14.35 & 1432 & TR & - & - & \(3.85\pm 3.02\) & - & - & - \\
26 & cy-cpenidene & 14.38 & 1434 & TR & \(1.17\pm 0.68\) & - & - & - & - \\
**27** & **x-cedema** & **14.40** & **1435** & **TR** & - & **-** & **3.76 \(\pm\) 1.55** & - & - & - \\
**28** & **caryophyllene** & **14.48** & **1441** & **TR** & - & - & **8.68 \(\pm\) 0.44** & - & - \\
29 & \(\beta\)-guirjumee & 14.60 & 1450 & TR & - & - & \(3.5\pm 2.02\) & - & - & - \\
30 & cy-gurjumee & 14.83 & 1467 & TR & - & - & \(0.17\) * & - & - \\
31 & germacrene D & 14.87 & 1469 & TR & \(21.67\pm 7.05\) & - & - & - & - & - \\
**32** & **humulene** & **14.95** & **1475** & **TR** & - & - & - & \(\mathbf{6.61\pm 0.4}\) & - & - \\
33 & p-selinee & 15.05 & 1483 & TR & - & - & \(11.81\pm 4.3\) & \(1.33\pm 0.11\) & - & - \\
34 & cy-selinee & 15.20 & 1493 & TR & - & - & - & \(4.9\pm 0.25\) & - & - \\
35 & valencene & 15.26 & 1497 & TR & - & - & - & \(1.17\pm 0.06\) & - & - \\
36 & cy-bulinesene & 15.41 & 1509 & TR & - & - & - & \(10.18\pm 1.86\) & - & - \\
37 & cy-drancesene & 15.46 & 1512 & TR & - & - & - & \(1.37\pm 0.12\) & - & - \\
38 & 4,11-selinalidene & 15.52 & 1517 & TR & - & - & - & \(9.22\pm 1.94\) & - & - \\
39 & cy-dcinene & 15.83 & 1542 & TR & - & - & \(1.03\pm 0.36\) & - & - \\
40 & bi-1-cyclooten-1-yl\({}^{\rm b}\) & 15.89 & 1546 & Cyc & - & - & \(1.2\pm 0.7\) & - & - & - \\ \multicolumn{4}{c}{_Kotens_} & & & & & & & \\
41 & 3-octanone & 7.35 & 988 & AL & \(14.65\pm 1.21\) & \(11.01\pm 1.83\) & \(15.57\pm 2.94\) & - & \(9.95\pm 5.75\) & \(13.83\pm 4.25\) \\
42 & valicato & 7.35 & 989 & TR & - & - & - & \(1.95\pm 0.38\) & - & - \\
43 & 22,6- & & & & & & & & \\
43 & trimethylcyclohexanone & 8.24 & 1042 & Cyc & - & \(0.91\) * & - & \(0.21\) * & - & - \\
44 & \(\alpha\)-isophorone & 8.66 & 1066 & TR & - & \(0.41\) * & - & - & - & - \\
45 & geranyl acetone & 14.70 & 1458 & TR & - & \(9\) * & - & \(0.76\pm 0.03\) & - & - \\
46 & \(\beta\)-ionone & 15.26 & 1497 & TR & - & \(1.79\pm 1.04\) & - & - & \(1.26\pm 0.79\) \\ \hline \end{tabular} RT—Retention time [min], RI—Experimental retention index calculated using a C7-C40 alkane standard. TR—Terpenoid, AL—Aliphatics, BP—Benzenoid/Phenylpropanoids, C5—C5-branched compounds, NS—Nitrogen- or sulfur-containing compounds, Cyc—Cyclic miscellaneous compounds. Number of analyses for each column = 4. Compounds in bold font were identified with an external standard in addition to mass spectral identification and retention index. \({}^{\rm a}\)—Compound was only detected once in the 4 headspace sample collections; thus, no standard error can be reported. \({}^{\rm b}\)—Compounds have not been detected from a natural source in the current literature.  
\end{table} 
Table 1: _Cont._  
Figure 1: (**A**)—Shows the distribution of compounds detected in the roots, shoots, and both plant parts for each of the graminoid plants. (**B**)—Shows the percentage distribution of the classes for the identified compounds for all samples analyzed. (**C**)—Shows a Venn diagram of the number of unique compounds detected for each of the three plants as well as the number of compounds found in two or all three plant species. TR—Terpenoid, AL—Aliphatics, BP—Benzenoid/Phenylpropanoids, C5—C5-branched compounds, NS—Nitrogen- or sulfur-containing compounds, Cyc—Cyclic miscellaneous compounds. In Figure 2, the distribution of grouped compounds found in each of the plant species is shown separately.