Carob (Ceratonia siliqua
) is a leguminous tree that reaches a height of around 15 m. It is grown in numerous countries, including Greece, Italy, Spain, Cyprus, and Israel. The pod is lined with a soft brownish pulp that may contain up to 50% sugar. The pulp is turned into carob flour that is used to make bread, cakes, and "chocolate". (Vaughan and Geissler 1997) The seeds are the source of locust bean gum.
Carob seeds, from which the word "carat" was apparently derived, were historically used as weights, reportedly because they are unusually consistent in weight, but Turnbull et al. (2006) investigated this question and found that the weight variation among carob seeds was not unusually low when compared to seeds of other plant species (Turnbull et al. 2006
and references therein).