Inflorescences take centre stage

Annals of Botany has a new special issue in Free Access: Inflorescences. It’s a useful reminder to me of another area of Botany I need to read more about.

For a start, I think I’ve said elsewhere that inflorescences are the structures where there are multiple flowers on a plant and not just a single flower. In a clumsy way this might be true but it also misses the point of an inflorescence. It’s not simply that there are multiple flowers, but also that those flowers work with each other as unit. They’re not just a collection of individuals.

If you approach inflorescences from this point of view, their structure becomes a bit of a puzzle. Why the diversity? But also, can you classify them sensibly and, if you can, what is the basis of that? Do different structures correspond with different functions?

Lawrence Harder and Przemyslaw Prusinkiewicz describe the interplay between inflorescence development and function as the crucible of architectural diversity. It highlights the importance of linking structures and function. In terms of tracing plant relationships, structure is useful but it’s also worth looking at what the structure does. A similar structure could have a very different result if the phenology, the timing of the flowering, changes.

Time is key factor that is highlighted by Harder and Prusinkiewicz. Looking at a display, it’s easy to think of it as an organisation in space, but they also make a point that inflorescences are dynamic. They change with time, and how they change with time has consequences for their function.

As far as plant reproduction goes, it’s easy to focus on the success of flowers, but Harder and Prusinkiewicz argue that what you have is part of a modular system, and that to understand it you have to look at the system as a whole, instead of modules in isolation. Most angiosperms use inflorescences so it’s clearly a powerful tool for a plant. Looking at them as a unit and not just parts can put plant reproduction into a new context.

Harder L.D. & Prusinkiewicz P. (2012). The interplay between inflorescence development and function as the crucible of architectural diversity, Annals of Botany, 112 (8) 1477-1493. DOI: http://dx.doi.org/10.1093/aob/mcs252