Question
What trees produce acrons

Answer
The acorn is the fruit of the oak tree (genera Quercus, Lithocarpus and Cyclobalanopsis, in the family Fagaceae). It is a nut, containing a single seed (rarely two seeds), enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1-6 cm long and 0.8-4 cm broad. Acorns take about 6 or 24 months (depending on the species) to mature; see List of Quercus species for details of oak classification, in which acorn morphology and phenology are important factors.

Acorns appear only on adult trees, and thus are often a symbol of patience and the fruition of long, hard labour. For example, an English proverb states that Great oaks from little acorns grow, urging the listener to wait for maturation of a project or idea. A German folktale has a farmer try to outwit Satan, to whom he has promised his soul, by asking for a reprieve until his first crop is harvested; he plants acorns and has many years to enjoy first. In Britain, one old tradition has it that if a woman carries an acorn on her person it will delay the aging process and keep her forever young. In the United States, botanists joke that even the greatest oak was once a little nut.

The Norse legend that Thor sheltered from a thunderstorm under an oak tree has led to the belief that having an acorn on a windowsill will prevent a house from being struck by lightning, hence the popularity of window blind pulls decorated as acorns. In ancient Japan, (Jomon period), acorn was an important food. They harvested, peeled and soaked acorns in natural or artificial ponds for several days to remove tannins, then processed it to make acorn cakes. In Korea, an edible jelly named dotorimuk is made from acorns.

A motif in Roman architecture and popular in celtic and scandinavian art, the symbol is used as an ornament on cutlery, jewelry, furniture, and appears on finials at Westminster Abbey. The Gothic name akran, German Eicher, etc., had the sense of "fruit of the unenclosed land". The word was applied to the most important forest produce, that of the oak. Chaucer spoke of "achornes of okes" in the 1300s. By degrees, popular etymology connected the word both with "corn" and "oak-horn", and the spelling changed accordingly.

In the 1600s, a juice extracted from acorns was administered to habitual drunkards to cure them of their condition or else to give them the strength to resist another bout of drinking. Young lovers may place two acorns, representing themselves and the object of their affection, in a bowl of water in order to predict whether they have a future together; if the acorns drift towards each other they are certain to marry (they will, if placed closer to each other than to the edge of the bowl).

By analogy with the shape, in nautical language, the word acorn also refers to a piece of wood keeping the vane on the mast-head.