1. Azizian D, Culter DF (1982) Anatomical cytological and phytochemical studies on Phlomis L. and Eremostachys Bunge (Labiatae). Bot J Linn Soc 85:249–281
2. Ball PW (1972) Stachys. In: Tutin TG, Heywood VH, Burgess NA, Moore DM, Valentine DH, Walter SM, Webb DA (eds). Flora Europaea, vol 3. Cambridge University Press, Cambridge, pp 151–157
3. Basset IJ, Munro DB (1986) Pollen morphology of the genus Stachys (Labiatae) in North America, with comparisons to some taxa from Mexico, Central and South America and Asia. Pollen et Spores 28:279–295
4. Bech TD (1963) Anatomic structure of the hairs of Phlomis pungens Willd. Ukr Antarkt Zh 20:96–98
5. Bentham G (1834) Labiatarum Genera et Species. Moyes N, London, p 783