(modifié de Coste, Flore de la France 1937) :
Arbrisseau ou arbuste de 3-10 mètres, rameaux étalés-dressés, arrondis, les jeunes et les bourgeons bientôt glabres ; bois nu très lisse;
Écologie : (répartition d'après la flore) Lieux frais ou humides, dans presque toute la France; nul dans la plaine méditerranéenne.
Répartition hors de France : Europe surtout centrale ; Asie centrale et boréale.
(modified from Butcher, British Flora 1961):
NOTE: the French text is more complete and up-to-date
A small tree 3-10 m. high, Twigs at first pubescent, later glabrous, reddish or dark brown, without raised striæ on the young wood beneath the epidermis.
Ecology UK: (distribution according to flora) common and widespread throughout the British Isles.
France:
Distribution outside France: ?
Fleurs : chatons précoces, gros, oblongs ou cylindriques, denses, subsessiles, à écailles velues, noirâtres au sommet; style court;
Floraison France : Mars-avril.
Flowers: Catkins appearing before the leaves, 20-45 mm long, at first erect, later spreading, subsessile; male ovoid; female broadly cylindrical; scales narrowly ovate, subacute, with long, silky hairs, brownish below the black upper portion. Stamens 2, filaments glabrous or slightly hairy, nectary cylindrical, short. Ovary hairy, ovoid-conical, pedicel slender, much longer than the nectary; stigma small, undivided, style usually shorter than the stigmas;
Flowering UK: late March-late April.
Please
consider 
