The almond (Prunus dulcis) is a species native to Iran. It is one of the oldest culivated trees in existence, as it can be propagated by seed, rather than grafting as most other top fruit trees. Almonds are known to have already been cultivated in the Early Bronze Age (3000-2000 BC) in Jordan, and from there it spread along the shores of the Mediterranean into northern Africa and southern Europe. In modern times it was introduced into America, and the commercial crop produced in California is now responsible for more than half the world's annual production of almonds.
Growing to about 8m tall at maturity, a large almond tree in full flower is a sight to behold, smothered in the most delicate of pink blossom. If pollination is good (and as they flower very early, they do need relatively warm spring weather for a succesful crop), the fruit which is offically a drupe, not a nut, will form - the edible seed completely covered by a thick silvery-green hull. When this starts to split open, that's a sign that the nuts inside are ripe and ready to harvest.