Jersey the island. The species is the subject of an ongoing programme to save it from extinction in Jersey via a collaboration between States of Jersey, Durrell Wildlife Conservation Trust and Jersey Amphibian and Reptile Group (JARG), with support and sponsorship from several other organisations. The programme includes captive breeding and release, public awareness and habitat restoration activities. Trees generally considered native are the alder ("Alnus glutinosa"), silver birch ("Betula pendula"), sweet chestnut ("Castanea sativa"), hazel ("Corylus avellana"), hawthorn ("Crataegus monogyna"), beech ("Fagus sylvatica"), ash ("Fraxinus excelsior"), aspen ("Populus tremula"), wild cherry ("Prunus avium"), blackthorn ("Prunus spinosa"), holm oak ("Quercus ilex"),
Prunus avium parent species of "Prunus cerasus" (sour cherry), by way of ancient crosses between it and "Prunus fruticosa" (dwarf cherry) in the areas where the two species overlap. All three species can breed with one another. "Prunus cerasus" is now a species in its own right, having developed beyond a hybrid and stabilised. Pliny distinguishes between "Prunus", the plum fruit, and "Cerasus", the cherry fruit. Already in Pliny quite a number of cultivars are cited, some possibly species or varieties, Aproniana, Lutatia, Caeciliana, and so on. Pliny grades them by flavour, including dulcis ("sweet") and acer ("sharp"). and goes so far