On the asymbiotic germination of some New Zealand spider orchids (Corybas).
Corybas is a large and widespread genus of terrestrial orchids, but little has been done to understand their germination. We tested germination of five species of helmet orchid (C. cheesemanii, C. dienemus, C. iridescens, C. macranthus and C. oblongus) on a range of asymbiotic media. Corybas macranthus germinated on four of seven tested media. From other species there was limited germination; for C. cheesemanii germination occurred for only two of five capsules collected concurrently and sown under the same conditions. The failure of filled seeds to germinate under optimal conditions could suggests the presence of seed dormancy. We trialed desiccation and warm moist stratification as methods to break dormancy, however this was unsuccessful.