These two links may help-

http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=132255

http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=132255

Hi Bernardo! You can try the respective volume of Flora Iberica, available online here:

http://www.floraiberica.es/floraiberica/texto/pdfs/03_067_01_Tamarix.pdf

Thks all. Your tips helped my identify the species I had found!

For the species present in North Africa a good source can be:

CHARCO, J. (2001). Guía de los árboles y arbustos del norte de África. Agencia Española de Cooperación Internacional. Madrid. 671 pp.

And for the species from Iberian Peninsula:

LÓPEZ GONZÁLEZ, G. (2004). Guía de los árboles y arbustos de la Península Ibérica y Baleares. 2ª edición corregida. Ediciones Mundi-Prensa. Madrid. 894 pp.

Hi Bernardo,

It would be good to know where The specimen was collected.

If it was in Portugal The Flora Iberica may work, though I wouldn´t trust identifications leading to T. dalmatica or T. mascatensis.

Just to be curious, Which was the result of your identification?

The best way is to use the local Flora will definitely helpful to you..

Jose the id keys led me to T. paviflora which in fact is an exotic specie that was already recorded in the area where this one was collected.

Hi Bernardo, sorry for the delay. 

It makes sense. T. parviflora is widely wsed as ornamental in the Iberian Peninsula, and it is easily found naturalized forming comunities alone or mixed with other Tamarix species.