Rosemary is a Salvia, but still rosmarinus

What do we gain by calling Rosemary Salvia rosmarinus? Oh, you hadn't heard. That tough and aromatic shrub in a pot by your backdoor that used to be called Rosmarinus officinalis has for the last four years been moved to the genus Salvia.

First up, keep calling it Rosemary. That will continue to work, and you'll be well understood. If you want to know a little about where it fits into the tree of life, what it's closest relatives are, or where you might find similar aromatics, think about the fact it is a Salvia.

Luckily in this case the species name carries the 'rosmarinus' flag for us. That doesn't always happen when taxonomists (those who review and change names, based on the rules of plant naming and the latest science) make a change like this.

Based on the latest DNA evidence - which we now use alongside how a plant looks to determine close relatives - Rosemary is embedded within the genus Salvia to such a degree that we either had to split up Salvia into many smaller genera or combine Rosmarinus and four other similar genera into Salvia.

This is relatively old news (from 2017) but sometimes we need reminding of why 'irritating' name changes like this are needed. After all, the name Rosmarinus officinalis (for Rosemary) has been with us as long as the name Salvia officinalis (for Sage). They date back to Carl Linnaeus's first use of the binomial (two-name - genus and species) system we use today, 1753.

As I say, it was luck that left us with Salvia rosmarinus and not Salvia laxiflorus, Salvia rigidus or Salvia tenuifolius. Those latter three names have also been used for this species but, thankfully, they were published later than 1852, when German botanist, Matthias Jakob Schleiden, coined the first name.

There is a little nomenclatural complexity embedded within that move by Schleiden but let's just say it worked out for the best.

If we look at the flowers of Rosemary we see two fertile stamens (tipped by the anthers, the pollen carrying parts), the same as other salvias, and different to four anthers found in most other genera in the mint family, Lamiaceae. That's the shared visible character that holds the new expanded genus together.

The stamens stick closely to that long purple stigma (the receptive stalk above the ovary) and can be a little difficult to see in the rather small flowers. In the picture above the anthers are paired at the base of the visible part of the purple style, in the picture at the top of the blog they extend almost to the end of the style. 

This new classification reminds us that Rosemary is not so different to Salvia in the structure of its flowers and in some of the aromatics in its leaves. They are more closely related to each other than they are to Mint (Mentha) and lots of others in this culinarily attractive plant family. That's good to know, and to be reminded of by the botanical name.