Basil That Spreads by Underground Runners?

I have searched your Q&A section, but did not find the answer that I need. A few years ago, I was given a basil, but the person did not know which variety it was. It was fantastic! I have since moved, and unfortunately did not take some with me. Here's where I am hoping you can help identify it and offer it in your catalog. It had a dark green leaf with purple semi-woody stems and light purple blooms. The most unusual fact about this plant is that it spread by runners underground, much like mint, but had no minty smell or flavor. In fact this was the strongest basil I have ever tasted. The closest to resemble it, that I have seen, is the African Purple. I hope you can help!

I don't know of any basil (Ocimum species) that spreads by runners. My guess is that you plant was another member of the mint family (basil is one of many herbs that belong to the mint family, the Lamiaceae). There are plenty of other members of the mint family that spread by runners, but none that I know of that has purple stems and a basil-like scent.