There are many sources for articles that pertain to the Botany of Salvia, such as Salvia.net - Botany, as well as a further article that website links to at Entheology.org and the ever-expanding Wikipedia entry on Salvia divinorum. We had an exhaustive article on the botany of Salvia reprinted here, but the author requested that TeachingPlants remove it and all mention of the author or links to his paper as well. This particular strain of Salvia has swept the world and has created a wake of controversy in its path. It's easy to think of Salvia divinorum only as the latest trend or continued fuel for raging controversy, which often leaves the botany of Salvia forgotten and ignored.
In short, Salvia divinorum is part of the massive genus Salvia, which boasts over 900 species. Salvia, more commonly known as sage, is used form everything from ornamentals in gardens, to cooking (sage, oregano, basil), to its use as a mystical herb by the Mazatecs of Oaxaca, Mexico. The genus Salvia itself belongs to the mint family Lamiacae (formerly known as Labiatae). It natively exists in just a small region of Oaxaca, Mexico, where it flourishes in its rocky mountain soil to this day. Salvia divinorum is quite a spindly, sprawling perennial that reaches heights of 4 to 6 feet, but only when the conditions are just right. The stems are square and hollow and are extremely easy to damage or break off completely, though, adding to the difficulties most amateur gardeners with high hopes face when trying to cultivate this rare and sacred plant. Even winds that are a little too windy can deal a great deal of damage to these delicate plants.
Further adding to the trouble, Salvia divinorum rarely seeds, even when cultivated by hand under controlled conditions. Even when it does seed, the seeds have an extremely low germination rate. This only adds more mystery to the botany of Salvia. Daniel Siebert is perhaps the most famous Salvia divinorum researcher and he has reportedly been able to produce seeds that have grown into mature plants, which, would then, make any plants cloned from them a new species of Salvia.
Oddly enough, in its natural habitat, Salvia typically propogates by falling over, and then sending out roots where the stem touches the ground. When the humidity is high enough, roots can often be seen forming at random places on the stem of the plant...making those points an ideal candidate for propogating the plant via cuttings.
We have even read that botanists familiar with Salvia botany beleive it is actually a cultigen. What does that mean? When speaking of the botany of Salvia divinorumin particular, it means that this plant that has been deliberately altered or selected by humans and the result of artificial selection! Is it possible that this plant didn't exist until humans entered the picture and started to work with it, altering a different plant that resulted in Salvia divinorum? Chances are that no matter how many research is done regarding the botany of Salvia and its true origins, we may never know for certain, only adding to the mystique of this sacred plant.