Fig. 1.

Mean enrichment factors (ε) for ¹³C and ¹⁵N of (A) fully mycoheterotrophic (FMH) Orchidaceae and Ericaceae and (B) partially mycoheterotrophic (PMH) Orchidaceae and Ericaceae associated with fungi forming ectomycorrhizas. Boxes represent one standard deviation of the mean ε values for the four significantly distinguished groups of (partially) mycoheterotrophic Orchidaceae and Ericaceae and for their respective photosynthetic reference plants (REF, n = 1433. Abbreviations of the species and numbers of replicates (n) are as follows: FMH Orchidaceae (n = 126): Apca, Aphyllorchis caudata; Apmo, A. montana; Ceda(a), Cephalanthera damasonium albino; Ceex, C. exigua; Celo(a), C. longifolia albino; Coma, Corallorhiza maculata; Cost, Corallorhiza striata; Cyab, Cymbidium aberrans; Cyma, C. macrorhizon; Epap, Epipogium aphyllum; Leni, Lecanorchis nigricans; Leth, Lecanorchis thalassica; Neni, Neottia nidus-avis; (REF, n = 628). FMH Ericaceae (n = 134): Hymo, Hypopitys monotropa; Monoun, Monotropa uniflora; Ptan, Pterospora andromedea; Pyap, Pyrola aphylla; Sasa, Sarcodes sanguinea; (REF, n = 403). PMH Orchidaceae (n = 189): Ceda, Cephalanthera damasonium; Ceer, C. erecta; Celo, C. longifolia; Ceru, C. rubra; Cotr, Corallorhiza trifida; Cygo, Cymbidium goeringii; Cyla, C. lancifolium; Epat, Epipactis atrorubens; Epdi, E. distans; Ephe, E. helleborine; Eple, E. leptochila; Liab, Limodorum abortivum; Litr, L. trabutianum; Plmi, Platanthera minor; (REF, n = 662). PMH Ericaceae (n = 606): Chum, Chimaphila umbellata; Moneun, Moneses uniflora; Orse, Orthilia secunda; Pych, Pyrola chlorantha; Pyja, P. japonica; Pymi, P. minor; Pypi, P. picta; Pyro, P. rotundifolia; (REF, n = 627).