| Summary: | There is no published information on the seed germination or seed storage physiology of <i>Lophomyrtus bullata</i>, <i>Lophomyrtus obcordata</i>, and <i>Neomyrtus pedunculata.</i> This lack of information is hampering conservation efforts of these critically endangered species. This study investigated the seed morphology, seed germination requirements, and long-term seed storage methods for all three species. The impact of desiccation, desiccation and freezing, as well as desiccation plus storage at 5 °C, −18 °C, and −196 °C on seed viability (germination) and seedling vigour was assessed. Fatty acid profiles were compared between <i>L. obcordata</i> and <i>L. bullata</i>. Variability in storage behaviour between the three species was investigated through differential scanning calorimetry (DSC) by comparing thermal properties of lipids. <i>L. obcordata</i> seed were desiccation-tolerant and viability was retained when desiccated seed was stored for 24 months at 5 °C. <i>L. bullata</i> seed was both desiccation- and freezing-sensitive, while <i>N. pedunculata</i> was desiccation-sensitive. DSC analysis revealed that lipid crystallisation in <i>L. bullata</i> occurred between −18 °C and −49 °C and between −23 °C and −52 °C in <i>L. obcordata</i> and <i>N. pedunculata</i>. It is postulated that the metastable lipid phase, which coincides with the conventional seed banking temperature (i.e., storing seeds at −20 ± 4 °C and 15 ± 3% RH), could cause the seeds to age more rapidly through lipid peroxidation. Seeds of <i>L. bullata</i>, <i>L. obcordata</i> and <i>N. pedunculata</i> are best stored outside of their lipid metastable temperature ranges.
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