The chocolate tree, or Theobroma Cacao originates in South America. It is a "lower rainforest canopy" plant, and thrives in damp warm conditions with partial shade. The plant germinates from a cocoa bean, which quickly spouts and splits, producing a stem that produces new single-stalked leaves at its apex as it grows. Leaves are initially a translucent red, hanging down vertically on the ends of horizontal stalks. Hanging vertically allows the limp growing leaf to expand quickly, with water more easily able to reach all parts of the expanding leaf, and without the shape needing support. The damp growing leaf and its stalk quickly expand from a few millimetres in length to the size of an adult human hand in just a few days, then harden and turn a medium dark green. Adult Leaves are paper-thin and do not hold a great deal of moisture. This makes them difficult to digest for insects, and their fast growth-phase means that the initial window of vulnerability is small. Leaves and stems also have fine hairs to make it more difficult for insects to travel over the plant. Once the leaf has attained maturity, a muscle-like swelling at the base of the stem and the base of the leaf raise it up to face the light. The thin, dry leaves are vulnerable to dehydration and overheating, and can easily turn brown around the edges, and ultimately drop. These fallen leaves can take a surprisingly long time to biodegrade, and can remain on the ground under the plant, propped up at an angle by the attached stalk, for many months. a spread of this leaf litter allows water through to the ground while depriving any competing seedlings of light near the plant's base. Once the single stalk has reached a certain size it will produce a crown of new stems, each of which then grows like the original. Until this point, the plant may look like "a straight stick with leaves". Crowning can be induced early (to produce a tree with more branching) by deliberately damaging the stem tip, although this risks damaging the plant. The stem also also has soft green thin flexible spikes around the stems. In an adult tree, some of these should change into flowers, resulting in large sweet-tasting yellow or orange seed-pods, containing large bitter seeds. When roasted and processed, these brown seeds (the cocoa beans) are the base material for chocolate. Amongst its other unusual properties, the lipid obtained from cocoa beans (cocoa butter) is supposed to have the highest melting point of any raw vegetable fat, and is supposed to be the only plant oil or fat that remains solid up to almost human body temperature. This melting point is part of why chocolate dissolves so well in the mouth. copyright © E. Baird, 2007 |