The phenological growth stages of Megacarpaea polyandra Benth. ex Madden: a high valued traditional medicinal plant of the Himalaya

Phenological studies of medicinal plants have been less explored especially for plants confined in the Himalayan region (India). Here we describe detailed phenological stages of Megacarpaea polyandra Benth. ex Madden. This perennial species belongs to the family Brassicaceae and is commonly known as Barmola or Barmau, being a highly valued traditional endemic medicinal plant of Himalaya. Seven principal growth stages from seed germination to senescence as per BBCH (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) scale have been described along with secondary growth stages. Barmola exhibited a long juvenile vegetative phase (~ 3 to 4 years) compared to the short reproductive development typical of long-lived semelparous species. The long vegetative phase is characterized by leaf development coupled with an increase in root size. Roots constitute the storage organ from which Barmola translocates resources for development in subsequent periods. At the time of inflorescence emergence (last growth cycle), Barmola root’s reached their maximum size, and the translocation of resources coupled with leaf development sustain the reproductive effort of this species, culminating then with fruit ripening and plant death. The application of the BBCH scale was useful to identify the leaf development phase as the most critical growth stage on Barmola. Future conservation strategies aimed to protect Barmola wild populations should incentive the cultivation of this species to warrant their sustainable use among farmers from the Himalayas.