Table 2.

Gas chromatographic¹ and mass spectral data from analysed species

Peak	RI2	mass spectrometric fragmentation m/z (rel. intensity)	Compound	P. krivolutskyi	S. continentalis
1	915	126 (M+, 2), 111 (2), 99 (6), 98 (54), 97 (31), 84 (6), 83 (16), 71 (24), 70 (30), 69 (19), 57 (6), 56 (21), 55 (100), 43 (82)	4-ethylhex-1-en-3-one*	97.8	96.8
2	1606	252 (M+, 16), 154 (10), 153 (100), 135 (12), 125 (5), 109 (16), 107 (12), 93 (14), 83 (21), 81 (14), 71 (49), 69 (31), 57 (23), 55 (28), 43 (36)	2-ethyl-1-(6-(pentan-3-yl)-3,4-dihydro-2H-pyran-2-yl) butan-1-one**	2.2	3.2

¹Main compounds are given as relative ratios to each other and are representing mean values of all examined extracts: Three extracts of P. krivolutskyi (including pooled extract as well as individual extract), and four pooled extracts of S. continentalis. ² RI was calculated according to van den Van den Dool and Kratz (1963),^*RI and mass spectrum showed full correspondence with synthesised compound (SI Figure S3), ^**tentative