Morpho-anatomical Observations on Homoeopathic Plant Drug Hygrophila spinosa T. Anderson, Verma, Digvijay, Singh Shilpi, Arya Renu, Rajan Soundararajan, Arya Bhopal Singh, Khurana Anil, and Manchanda Raj Kumar , Pharmacognosy Journal, February 2019, Volume 11, Issue 2, p.286-291, (2019)