Tarragon is a hardy herbaceous perennial of the large genus Artemisia in the family Asteraceae. It may have originated in central Asia. The species dracunculus, known as Russian or Siberian tarragon, reproduces by seed. The far tastier clone we now call the cultivar 'Sativa' originated centuries ago and has been considered so worthwhile that it has been propagated by root divisions and cuttings ever since. The seed of A. dracunculus ‘Sativa,’ rarely produced, is almost always sterile. Dracunculus, meaning "little dragon," may refer to the coiled and twisted roots, or to the fact that tarragon was thought to cure the bites and stings of venomous beasts and mad dogs. Tarragon grows from old roots each year to 2 to 3 feet in height. It is many-branched and gets semi-woody. The leaves are smooth, dark green, narrow and pointed on the upper parts of the plant and may be 3 inches long on mature plants but are usually shorter. They taste like anise and can numb the tip of the tongue when chewed. In contrast, Russian tarragon has lighter green leaves that are not so smooth, and their flavor is grassy and without the anise hint or the power to numb. It follows that seed-grown plants should be avoided and only plants grown from cuttings or divisions should be propagated and bought. The taste test will always distinguish one from the other.
Herb Society of America : Grow : HSA Publications : Quick .., http://www.herbsociety.org/grow/hsa-publications/hsa-quick-fact-sheets.html (accessed January 20, 2017).