Basidia and spores of the bird's nest fungus <i><a href="//commons.wikimedia.org/wiki/Cyathus_olla" title="Cyathus olla">Cyathus olla</a></i>.  Figures renumbered. <br>"1-3. Mature basidia with two, three, and four spores; <br>4. Basidium collapsing with spores still attached; <br>5. Spores immediately after separation from basidia, showing conspicuous apiculus; <br>6. Older spores; apiculus nearly or quite gone."
George W. Martin
1927
Martin, GW. (1927). Basidia and spores of the Nidulariaceae. <i>Mycologia</i> <b>19</b>(5): 239-247. Plate 22.