Phenomorphology and eco-morphological characters of Rhododendron lauroid forests in the Western Mediterranean (Iberian Peninsula, Spain)

The evergreen broad-leaved forest of Rhododendron ponticum represents a special type of Mediterranean vegetation because of their relict nature (allegedly pre-glacial, Southern-Iberian and Pontic) and connection with Macaronesian-Atlantic flora. The findings of ecomorphological (growth forms) and phenological (phenology) studies point to characteristics typical of its relict character and its relationship with subtropical lauroid vegetation (greater forest stratification, larger leaves, high percentage of photosynthetic stems, scarce tomentosity, pre-flowering in a season different to Mediterranean species and closeness of autumn-winter flowering species). There are, however, links with typical Mediterranean vegetation (Quercus L. forests) that surrounds the Rhododendron stands, due to its adaptation to Mediterranean climate (sclerophyll leaves, plant and leaf duration, post-fire regeneration, fleshy fruit and fruit setting-seed dispersal seasonality). Within the community, different groups of plants show different adaptations to the same biotope, suggesting their distinct paleo-phytogeographical origins. The results confirm the singularity of this vegetation within the typically Mediterranean environment where it grows and its connections with other extra-Mediterranean types.