The evolution of medicinal floras: insights from Moroccan medicinal plant knowledge transmission

Abstract

Why some plants are used medicinally, and others not, is not yet totally understood; intrinsic, cultural and floristic factors may be important and their interactions are complex. Plants’ morphological, organoleptic and ecological traits have been evaluated elsewhere. This thesis focuses on the role of cultural transmission of knowledge across generations, societies and floristic environments. Using Morocco as a case study, this thesis describes medicinal plant use among understudied Tashelhit speakers in the High Atlas and specialist healers called ferraggat. The role of knowledge transmission is evaluated in a context of cultural change. Processes of transmission are also inferred from patterns of medicinal plant use regionally; a checklist for Moroccan medicinal plants is compiled and a new method based on biogeographic data is used to test a hypothesis about the influence of the Arab knowledge due to historical migrations into Morocco. Aspects of Ishelhin ethnobotanical knowledge are described through 254 vernacular plant names, which reflect local livelihoods and biodiversity values; 151 vernacular names for medicinal plants correspond to 159 botanical species and are found to treat 36 folk ailments. Men and women listed significantly different medicinal plants; herbal medicine is a women’s domain characterized by low specificity of herbal remedies and widespread use of mixtures. Medicinal plant use is guided by local concepts of health and illness including supernatural aetiologies, which also determine healthcare seeking behaviour. Belief in supernatural causes of illness and difficult access to biomedicine result in preference for ferraggat to treat childrens’ ailments in the High Atlas by a practice called frigg. Seventy plants were documented for this treatment, but emphasis on plants may be a recent substitute for remedies that used primarily wool and blood two generations ago. This is a shift in the objects of cultural meaningfulness in response to the increasing influence of orthodox Islam and state-sponsored modernisation, including public healthcare and schooling. Transmission of knowledge is underpinned by the prestige and legitimacy of alternative remedies and healing systems, which shift during socioeconomic and religious change. With biomedicine available, herbal remedies may not be preferred treatments, unless local explanatory models of illness are maintained. Meta-analysis of the Moroccan medicinal flora supports this view. Although I hypothesised that Saharo-Arabian plants would be overrepresented in the Moroccan medicinal flora, overrepresentation was not significant. Nonetheless, Arabic influence is evidenced through the Moroccan syncretic health system. The combination of pattern and process observation in the field and from macroscale analysis contributes to the understanding of how knowledge transmission shapes medicinal floras