Micheli discovers that fungi have spores

In 1729 the Florentine botanist Pier Antonio Micheli published Nova plantarum genera. In a world where fungi were still often explained by spontaneous generation from damp earth or decaying matter, Micheli treated them as organisms with reproductive structures of their own. He observed the fine dust released by fruiting bodies, sowed it on prepared substrate and described the appearance of fungi resembling the parent organism.

His working methods did not resemble a modern laboratory with controls and statistical analysis, so a historical experiment should not be read like a present-day protocol. What mattered was the change of question: instead of asking what spoiled matter a fungus had "arisen" from, Micheli looked for continuity between a spore and a new organism. The engravings showed structures seen through simple microscopes, and the text allows the course of the observations to be followed today in the first edition.

Nova plantarum genera contained descriptions of around 1,900 organisms, including hundreds of fungi and lichens, and 73 plates. Micheli introduced generic names still in use today, among them Aspergillus and Botrytis, although their modern scope need not correspond exactly to his concepts. Nomenclature changed many times afterwards, whereas the method of linking spore structure to classification became a foundation of mycology.

The significance of the event does not, therefore, lie in a single "discovery of spores" in today's sense. Micheli demonstrated a research programme: fungi can be propagated, compared and ordered on the basis of observable characters. The available scan of the work makes it possible to separate later legend from what he actually drew and described.

From spore to a new colony

Micheli’s strongest evidence was not merely an illustration of spores, but an attempt to connect them with reproduction. Harvard University Herbaria reports that he observed spores across all the fungal groups he studied, described asci, and cultured fungi from spores. That moved the case from resemblance toward experiment: the minute bodies were neither dust nor products of decay, but parts of a life cycle. The scale of Nova plantarum genera also made the work inspectable: it covered about 900 fungi and lichens and contained 73 plates; Harvard specifically identifies Table 86 as a copper engraving of Peziza and Helvella. BHL’s complete scan lets readers compare descriptions with images rather than rely on a later origin story.