Supporting Information
Appendix 1 . Germination and seedling transplant methods
Supplementary Figure 1. The detailed population and germination strategy allocations across blocks with the targeted temperature regime and the seasons. Population names are coloured based on germination strategy and followed by seedling germination season if two germination timings occurred within a population. Germination strategies were: Immediate (I), Staggered (S), Postponed (P), and Postponed-deep (PD); autumn (early) germinating seed was coded as ‘(/au)’ and spring (late) germinating seed as ‘(/sp)’. Where plant availability was low, extra pots were placed into the experiment to ensure equivalent neighbour effects for all pots. Those extras were not part of the analysis and the pots are shown with grey labels. Red asterisks indicate individuals from which seed was sourced for the trans-generational experiment. Each pot contained one plant. Pots with orange pin (without plant; pot number 83, 93, 182, 192, 263, 278, 441 and 451) were the pots allocated for i-Buttons (3 i-Buttons below the soil and 1 i-Button above the soil) in each block.
Supplementary Figure 2. The realised mean temperature in ambient and warm conditions during the day at a) plant level 15 cm above the pot, and b) 8 cm below the soil surface; and during the night, c) plant level 15 cm above the pot, and d) 8 cm below the soil surface. At each season, warm conditions were significantly warmer than ambient (p < 0.001, ANOVA). Note: data loggers for plant level temperatures were only started in winter. The boxes along the bottom of the figure indicate the target soil temperatures for ambient (A) and warm (W) treatment for each season.
Supplementary Figure 3. Offspring germination of the staggered strategy under ambient germination temperature over time (indicated by x-axis). Lines indicate which individual (mother plant) produced the seeds; each line represents 100 seeds. Line colour and style indicate maternal soil temperature – solid blue for ambient soils and dashed orange for warmer soil temperatures.
Supplementary Table 1. The distribution of population and germination strategies (GS) across the blocks: Immediate (I), Staggered (S), Postponed (P), and Postponed-deep (PD). Population name reflects the collection sites: Namadgi (Nam), Kosciuszko (Kos), Victoria (Vic), and Tasmania (Tas). Seeds for each population were bulk sampled from multiple plants. There was imbalance in the distribution of germination strategies across blocks, but this was not so extensive as to be an impediment to statistical analyses. Accessions with grey font are those re-determined as other Oreomyrrhis species, new species ID in bracket, and thus were excluded in the analyses.
Supplementary Table 2. Significance of the germination strategy (GS) and warming (SoilT) on the vegetative, reproductive traits, and phenology. Generalized Linear Mixed model and Linear Mixed Model were used to analyse the data with fixed term as GS×SoilT. The random term was population nested in block (block/pop). Plant area and aboveground biomass were transformed using natural logarithms. In the direction column, GS are noted as Immediate (I), Staggered (S), Postponed (P), and Postponed-deep (PD) and SoilT are as Ambient (A) and Warm (W).
Table S3. Transgenerational effects on germination traits. The significance of germination strategy (GS), soil temperature (SoilT), and germination temperature (GermT). The analyses were performed using mixed models with GS×SoilT×GermT as fixed and population and individual plant nested in shelf as random factors.