In vivo and in vitro microscopic study of leaves from Thymus baeticus Boiss. ex Lacaita

We performed an histologic study comparing 'in vivo' and 'in vitro' leaves of Thymus baeticus Boiss. ex Lacaita. 'In vitro' leaves were obtained through organ culture, whereas wild material - 'in vivo' leaves - was collectd in Lanjaron (Granada, Espana). Both samples showed similar oil-glands, which resembled the general pattern in Labiatae; however, we noticed remarkable differences as far as shape and hairs were concerned. These facts are thought to be caused by the environment: cultured plants grow in optimum conditions, so they do not develop their defensive mechanism as much as wild plants do. These conclusions are reinforced by the study of powdered leaves.