Table 1.

Why common uses and conservation of certain edible and medicinal plants depend on local knowledge? Examples consider the best quality materials and safety for users.

Species Latin name Species common name (PT/GB)1	Main use	Useful LK	Practices that promote conservation & best use2
Arnica montana L. arnica/mountain arnica Fragaria vesca L. amiródio/wild strawberry Physospermum cornubiense (L.) DC. anis/bladderseed Tuberaria lignosa (Sweet) Samp. alcária/similar to rockrose	Medicinal Claimed to have potent anti-inflammatory effect and high demanded	Grown in very specifics habitats. Inconspicuous, are unnoticed. Skillful gathers find them searching some particular soil characteristics. Few people know the best sites, gathering periods, plant grow stages and how to prepare remedies	Maintaining a balance between wilderness and extensive management of woodlands and scrublands, promoting some disturbance to limit competition but avoiding great disturbances, resulting in the removal of large amounts of biomass
Borago officinalis L. borragem/borage Bryonia dioica Jacq. norça/white bryony Crataegus monogyna Jacq. espinheiro/hawthorn Origanum vulgare L. oregão/oregano	Food and medicinal Supplements, restoratives and condiments Digestive, respiratory, cardiovascular affections	Different parts and different grow stages of the same plant may be used for several purposes and prepared in many ways, according to specific circumstances and need s.	Extensive farming, avoiding pesticides and fertilizers Clearing, mowing, maintaining pathways, road slopes and properties borders (vegetation and traditional stone walls)
Montia fontana L. merujes/water blinks Portulaca oleracea L beldroega/green purslane	Food Consumed mainly raw	Abilities to clearly identify morphological features and convenient gathering sites are fundamental	Surface water management Cleaning of pathways Extensive farming
Arenaria montana L. seixinha/mountain sandwor Thymus pulegioides L. pojinha/broad-leaved thym Chondrilla juncea L. ginjeira/nakedweed	Medicinal Medicinal Food and medicinal	The best material should be gathered in managed sites such as clearings in oak forests, crop lands and meadows, which involve knowledge and proficiency	Woodlots and meadows management and extensive farming, avoiding pesticides and fertilizers
Geranium robertianum L. Erva- de- S. Roberto/herb Robert Hypericum perforatum L. piricão fêmea/St John's wort	Medicinal Oral use Digestive system and diuretic	Skills to identify certain morphological characters and to avoid confusion among similar species, with no medicinal value	Keeping traditional land tenure (communal versus fenced individual plots) and natural boundaries, preserving the best habitat and material
Tamus communis L. black bryonie	Food and medicinal	Toxic plants. Both gathering and uses require expertise to guarantee consumers safety	Woodland management as fruiting plants (used for remedies) are only available in clearings
Pterospartum tridentatum (L.) Willk carqueja/similar to brooms			Scrubland management avoiding fires and invasive species

1. For each species we present the most cited common name although there are others in the studied area.

2. The presence of some of these species is really affected by abandonment and changing in cover and agricultural practices. Nevertheless, according to our informants, those still occurring and existing, have different food and medicinal properties which may have impact in quality and safety. LK is needed to an integrated and sustainable management of habitats and plant materials.